diff --git a/src/CLI2.cpp b/src/CLI2.cpp
index 408da2933..c5fbd638c 100644
--- a/src/CLI2.cpp
+++ b/src/CLI2.cpp
@@ -162,7 +162,7 @@ void A2::decompose ()
 
       if (name == "rc")
       {
-        if (!mod.empty())
+        if (mod != "")
           tag ("CONFIG");
         else
           tag ("RC");
@@ -258,7 +258,7 @@ bool CLI2::getDataLocation (int argc, const char** argv, Path& data)
   if (value == nullptr)
   {
     std::string location = Context::getContext ().config.get ("data.location");
-    if (!location.empty())
+    if (location != "")
       data = location;
     return false;
   }
@@ -573,7 +573,7 @@ void CLI2::addContextFilter ()
 
   // Detect if any context is set, and bail out if not
   std::string contextName = Context::getContext ().config.get ("context");
-  if (contextName.empty())
+  if (contextName == "")
   {
     Context::getContext ().debug ("No context.");
     return;
@@ -595,7 +595,7 @@ void CLI2::addContextFilter ()
   Context::getContext ().debug ("Applying context: " + contextName);
   std::string contextFilter = Context::getContext ().config.get ("context." + contextName);
 
-  if (contextFilter.empty())
+  if (contextFilter == "")
     Context::getContext ().debug ("Context '" + contextName + "' not defined.");
   else
   {
@@ -635,14 +635,14 @@ void CLI2::prepareFilter ()
     {
       if (a.hasTag ("FILTER"))
       {
-        if (!combined.empty())
+        if (combined != "")
           combined += ' ';
 
         combined += a.attribute ("raw");
       }
     }
 
-    if (!combined.empty())
+    if (combined.size ())
       Context::getContext ().footnote (std::string ("Filter: ") + combined);
   }
 }
@@ -704,7 +704,7 @@ bool CLI2::canonicalize (
 ////////////////////////////////////////////////////////////////////////////////
 std::string CLI2::getBinary () const
 {
-  if (!_args.empty())
+  if (_args.size ())
     return _args[0].attribute ("raw");
 
   return "";
@@ -743,14 +743,14 @@ const std::string CLI2::dump (const std::string& title) const
 
   out << '\n';
 
-  if (!_args.empty())
+  if (_args.size ())
   {
     out << "  _args\n";
     for (const auto& a : _args)
       out << "    " << a.dump () << '\n';
   }
 
-  if (!_id_ranges.empty())
+  if (_id_ranges.size ())
   {
     out << "  _id_ranges\n    ";
     for (const auto& range : _id_ranges)
@@ -764,7 +764,7 @@ const std::string CLI2::dump (const std::string& title) const
     out << '\n';
   }
 
-  if (!_uuid_list.empty())
+  if (_uuid_list.size ())
   {
     out << "  _uuid_list\n    ";
     for (const auto& uuid : _uuid_list)
@@ -1229,7 +1229,7 @@ void CLI2::desugarFilterAttributes ()
 
       // An unquoted string, while equivalent to an empty string, doesn't cause
       // an operand shortage in eval.
-      if (value.empty())
+      if (value == "")
         value = "''";
 
       // Some values are expressions, which need to be lexed. The best way to
@@ -1278,7 +1278,7 @@ void CLI2::desugarFilterAttributes ()
         rhs.tag ("FILTER");
 
         // Special case for '<name>:<value>'.
-        if (mod.empty())
+        if (mod == "")
         {
           op.attribute ("raw", "=");
           rhs.attribute ("raw", value);
@@ -1515,7 +1515,7 @@ void CLI2::findIDs ()
     // listed as a MODIFICATION.
     std::string command = getCommand ();
 
-    if (_id_ranges.empty() &&
+    if (! _id_ranges.size () &&
         filterCount == 0     &&
         command != "add"     &&
         command != "log")
@@ -1606,7 +1606,7 @@ void CLI2::findUUIDs ()
       }
     }
 
-    if (_uuid_list.empty())
+    if (! _uuid_list.size ())
     {
       for (auto& a : _args)
       {
@@ -1655,8 +1655,8 @@ void CLI2::insertIDExpr ()
 {
   // Skip completely if no ID/UUID was found. This is because below, '(' and ')'
   // are inserted regardless of list size.
-  if (_id_ranges.empty() &&
-      _uuid_list.empty())
+  if (! _id_ranges.size () &&
+      ! _uuid_list.size ())
     return;
 
   // Find the *first* occurence of lexer type set/number/uuid, and replace it
@@ -1759,8 +1759,8 @@ void CLI2::insertIDExpr ()
         }
 
         // Combine the ID and UUID sections with 'or'.
-        if (!_id_ranges.empty() &&
-            !_uuid_list.empty())
+        if (_id_ranges.size () &&
+            _uuid_list.size ())
           reconstructed.push_back (opOr);
 
         // Add all UUID list items.
@@ -2033,7 +2033,7 @@ void CLI2::defaultCommand ()
     {
       // Apply overrides, if any.
       std::string defaultCommand = Context::getContext ().config.get ("default.command");
-      if (!defaultCommand.empty())
+      if (defaultCommand != "")
       {
         // Modify _args, _original_args to be:
         //   <args0> [<def0> ...] <args1> [...]
diff --git a/src/Context.cpp b/src/Context.cpp
index 5a650cd8f..05470720e 100644
--- a/src/Context.cpp
+++ b/src/Context.cpp
@@ -779,7 +779,7 @@ int Context::dispatch (std::string &out)
 {
   // Autocomplete args against keywords.
   std::string command = cli2.getCommand ();
-  if (!command.empty())
+  if (command != "")
   {
     updateXtermTitle ();
     updateVerbosity ();
@@ -1026,7 +1026,7 @@ void Context::getLimits (int& rows, int& lines)
 
   // This is an integer specified as a filter (limit:10).
   auto limit = config.get ("limit");
-  if (!limit.empty())
+  if (limit != "")
   {
     if (limit == "page")
     {
@@ -1106,7 +1106,7 @@ void Context::staticInitialization ()
 void Context::createDefaultConfig ()
 {
   // Do we need to create a default rc?
-  if (!rc_file._data.empty() && ! rc_file.exists ())
+  if (rc_file._data != "" && ! rc_file.exists ())
   {
     if (config.getBoolean ("confirmation") &&
         ! confirm ( format ("A configuration file could not be found in {1}\n\nWould you like a sample {2} created, so Taskwarrior can proceed?", home_dir, rc_file._data)))
@@ -1240,7 +1240,7 @@ void Context::updateXtermTitle ()
 void Context::updateVerbosity ()
 {
   auto command = cli2.getCommand ();
-  if (!command.empty() &&
+  if (command != "" &&
       command[0] == '_')
   {
     verbosity = {"nothing"};
diff --git a/src/DOM.cpp b/src/DOM.cpp
index 33573be8c..d310f21f9 100644
--- a/src/DOM.cpp
+++ b/src/DOM.cpp
@@ -63,7 +63,7 @@
 bool getDOM (const std::string& name, Variant& value)
 {
   // Special case, blank refs cause problems.
-  if (name.empty())
+  if (name == "")
     return false;
 
   auto len = name.length ();
@@ -111,7 +111,7 @@ bool getDOM (const std::string& name, Variant& value)
       std::string commandLine;
       for (auto& arg : Context::getContext ().cli2._original_args)
       {
-        if (!commandLine.empty())
+        if (commandLine != "")
            commandLine += ' ';
 
         commandLine += arg.attribute("raw");
@@ -158,7 +158,7 @@ bool getDOM (const std::string& name, Variant& value)
       std::string commandLine;
       for (auto& arg : Context::getContext ().cli2._original_args)
       {
-        if (!commandLine.empty())
+        if (commandLine != "")
            commandLine += ' ';
 
         commandLine += arg.attribute("raw");
@@ -242,17 +242,17 @@ bool getDOM (const std::string& name, Variant& value)
 bool getDOM (const std::string& name, const Task& task, Variant& value)
 {
   // Special case, blank refs cause problems.
-  if (name.empty())
+  if (name == "")
     return false;
 
   // Quickly deal with the most common cases.
-  if (!task.data.empty() && name == "id")
+  if (task.data.size () && name == "id")
   {
     value = Variant (static_cast<int> (task.id));
     return true;
   }
 
-  if (!task.data.empty() && name == "urgency")
+  if (task.data.size () && name == "urgency")
   {
     value = Variant (task.urgency_c ());
     return true;
@@ -295,13 +295,13 @@ bool getDOM (const std::string& name, const Task& task, Variant& value)
   {
     // Now that 'ref' is the contextual task, and any ID/UUID is chopped off the
     // elements vector, DOM resolution is now simple.
-    if (!ref.data.empty() && size == 1 && canonical == "id")
+    if (ref.data.size () && size == 1 && canonical == "id")
     {
       value = Variant (static_cast<int> (ref.id));
       return true;
     }
 
-    if (!ref.data.empty() && size == 1 && canonical == "urgency")
+    if (ref.data.size () && size == 1 && canonical == "urgency")
     {
       value = Variant (ref.urgency_c ());
       return true;
@@ -309,7 +309,7 @@ bool getDOM (const std::string& name, const Task& task, Variant& value)
 
     Column* column = Context::getContext ().columns[canonical];
 
-    if (!ref.data.empty() && size == 1 && column)
+    if (ref.data.size () && size == 1 && column)
     {
       if (column->is_uda () && ! ref.has (canonical))
       {
@@ -344,13 +344,13 @@ bool getDOM (const std::string& name, const Task& task, Variant& value)
       return true;
     }
 
-    if (!ref.data.empty() && size == 2 && canonical == "tags")
+    if (ref.data.size () && size == 2 && canonical == "tags")
     {
       value = Variant (ref.hasTag (elements[1]) ? elements[1] : "");
       return true;
     }
 
-    if (!ref.data.empty() && size == 2 && column && column->type () == "date")
+    if (ref.data.size () && size == 2 && column && column->type () == "date")
     {
       Datetime date (ref.get_date (canonical));
            if (elements[1] == "year")    { value = Variant (static_cast<int> (date.year ()));      return true; }
@@ -365,13 +365,13 @@ bool getDOM (const std::string& name, const Task& task, Variant& value)
     }
   }
 
-  if (!ref.data.empty() && size == 2 && elements[0] == "annotations" && elements[1] == "count")
+  if (ref.data.size () && size == 2 && elements[0] == "annotations" && elements[1] == "count")
   {
     value = Variant (static_cast<int> (ref.getAnnotationCount ()));
     return true;
   }
 
-  if (!ref.data.empty() && size == 3 && elements[0] == "annotations")
+  if (ref.data.size () && size == 3 && elements[0] == "annotations")
   {
     auto annos = ref.getAnnotations ();
 
@@ -399,7 +399,7 @@ bool getDOM (const std::string& name, const Task& task, Variant& value)
     }
   }
 
-  if (!ref.data.empty() && size == 4 && elements[0] == "annotations" && elements[2] == "entry")
+  if (ref.data.size () && size == 4 && elements[0] == "annotations" && elements[2] == "entry")
   {
     auto annos = ref.getAnnotations ();
 
diff --git a/src/Eval.cpp b/src/Eval.cpp
index de278aecb..6afc1e31e 100644
--- a/src/Eval.cpp
+++ b/src/Eval.cpp
@@ -218,7 +218,7 @@ void Eval::evaluatePostfixStack (
   const std::vector <std::pair <std::string, Lexer::Type>>& tokens,
   Variant& result) const
 {
-  if (tokens.empty())
+  if (tokens.size () == 0)
     throw std::string ("No expression to evaluate.");
 
   // This is stack used by the postfix evaluator.
@@ -229,7 +229,7 @@ void Eval::evaluatePostfixStack (
     if (token.second == Lexer::Type::op &&
         token.first == "!")
     {
-      if (values.empty())
+      if (values.size () < 1)
         throw std::string ("The expression could not be evaluated.");
 
       Variant right = values.back ();
@@ -242,7 +242,7 @@ void Eval::evaluatePostfixStack (
     else if (token.second == Lexer::Type::op &&
              token.first == "_neg_")
     {
-      if (values.empty())
+      if (values.size () < 1)
         throw std::string ("The expression could not be evaluated.");
 
       Variant right = values.back ();
@@ -755,14 +755,14 @@ void Eval::infixToPostfix (
     else if (token.second == Lexer::Type::op &&
              token.first == ")")
     {
-      while (!op_stack.empty() &&
+      while (op_stack.size () &&
              op_stack.back ().first != "(")
       {
         postfix.push_back (op_stack.back ());
         op_stack.pop_back ();
       }
 
-      if (!op_stack.empty())
+      if (op_stack.size ())
         op_stack.pop_back ();
       else
         throw std::string ("Mismatched parentheses in expression");
@@ -773,7 +773,7 @@ void Eval::infixToPostfix (
       char type2;
       unsigned int precedence2;
       char associativity2;
-      while (!op_stack.empty() &&
+      while (op_stack.size () > 0 &&
              identifyOperator (op_stack.back ().first, type2, precedence2, associativity2) &&
              ((associativity == 'l' && precedence <= precedence2) ||
               (associativity == 'r' && precedence <  precedence2)))
@@ -790,7 +790,7 @@ void Eval::infixToPostfix (
     }
   }
 
-  while (!op_stack.empty())
+  while (op_stack.size ())
   {
     if (op_stack.back ().first == "(" ||
         op_stack.back ().first == ")")
diff --git a/src/Filter.cpp b/src/Filter.cpp
index 88089ee8d..321b57aee 100644
--- a/src/Filter.cpp
+++ b/src/Filter.cpp
@@ -66,7 +66,7 @@ void Filter::subset (const std::vector <Task>& input, std::vector <Task>& output
     if (a.hasTag ("FILTER"))
       precompiled.push_back (std::pair <std::string, Lexer::Type> (a.getToken (), a._lextype));
 
-  if (!precompiled.empty())
+  if (precompiled.size ())
   {
     Eval eval;
     eval.addSource (domSource);
@@ -112,7 +112,7 @@ void Filter::subset (std::vector <Task>& output)
   // Shortcut indicates that only pending.data needs to be loaded.
   bool shortcut = false;
 
-  if (!precompiled.empty())
+  if (precompiled.size ())
   {
     Timer timer_pending;
     auto pending = Context::getContext ().tdb2.pending.get_tasks ();
diff --git a/src/Hooks.cpp b/src/Hooks.cpp
index 21c25344a..d4f5a3897 100644
--- a/src/Hooks.cpp
+++ b/src/Hooks.cpp
@@ -135,7 +135,7 @@ void Hooks::onLaunch () const
   Timer timer;
 
   std::vector <std::string> matchingScripts = scripts ("on-launch");
-  if (!matchingScripts.empty())
+  if (matchingScripts.size ())
   {
     for (auto& script : matchingScripts)
     {
@@ -188,7 +188,7 @@ void Hooks::onExit () const
   Timer timer;
 
   std::vector <std::string> matchingScripts = scripts ("on-exit");
-  if (!matchingScripts.empty())
+  if (matchingScripts.size ())
   {
     // Get the set of changed tasks.
     std::vector <Task> tasks;
@@ -250,7 +250,7 @@ void Hooks::onAdd (Task& task) const
   Timer timer;
 
   std::vector <std::string> matchingScripts = scripts ("on-add");
-  if (!matchingScripts.empty())
+  if (matchingScripts.size ())
   {
     // Convert task to a vector of strings.
     std::vector <std::string> input;
@@ -316,7 +316,7 @@ void Hooks::onModify (const Task& before, Task& after) const
   Timer timer;
 
   std::vector <std::string> matchingScripts = scripts ("on-modify");
-  if (!matchingScripts.empty())
+  if (matchingScripts.size ())
   {
     // Convert vector of tasks to a vector of strings.
     std::vector <std::string> input;
@@ -601,7 +601,7 @@ int Hooks::callHookScript (
   {
     Context::getContext ().debug ("Hook: output");
     for (const auto& i : output)
-      if (!i.empty())
+      if (i != "")
         Context::getContext ().debug ("  " + i);
 
     Context::getContext ().debug (format ("Hook: Completed with status {1}", status));
diff --git a/src/TDB2.cpp b/src/TDB2.cpp
index 6d224189f..daeb56688 100644
--- a/src/TDB2.cpp
+++ b/src/TDB2.cpp
@@ -123,7 +123,7 @@ bool TF2::get (const std::string& uuid, Task& task)
   if (! _loaded_tasks)
     load_tasks ();
 
-  if (!_tasks_map.empty() && uuid.size () == 36)
+  if (_tasks_map.size () > 0 && uuid.size () == 36)
   {
     // Fast lookup, same result as below. Only used during "task import".
     auto i = _tasks_map.find (uuid);
@@ -263,8 +263,8 @@ void TF2::commit ()
   if (_dirty)
   {
     // Special case: added but no modified means just append to the file.
-    if (_modified_tasks.empty() && _purged_tasks.empty() &&
-        (!_added_tasks.empty() || !_added_lines.empty()))
+    if (!_modified_tasks.size () && !_purged_tasks.size () &&
+        (_added_tasks.size () || _added_lines.size ()))
     {
       if (_file.open ())
       {
@@ -920,7 +920,7 @@ void TDB2::revert_pending (
       Context::getContext ().debug ("TDB::revert - task found in pending.data");
 
       // Either revert if there was a prior state, or remove the task.
-      if (!prior.empty())
+      if (prior != "")
       {
         *task = prior;
         std::cout << STRING_TDB2_REVERTED << '\n';
@@ -953,7 +953,7 @@ void TDB2::revert_completed (
       Context::getContext ().debug ("TDB::revert_completed - task found in completed.data");
 
       // Either revert if there was a prior state, or remove the task.
-      if (!prior.empty())
+      if (prior != "")
       {
         *task = prior;
         if (task->find ("status:\"pending\"")   != std::string::npos ||
@@ -1003,7 +1003,7 @@ void TDB2::revert_backlog (
       found = true;
 
       // If this is a new task (no prior), then just remove it from the backlog.
-      if (!current.empty() && prior.empty())
+      if (current != "" && prior == "")
       {
         // Yes, this is what is needed, when you want to erase using a reverse
         // iterator.
@@ -1055,7 +1055,7 @@ void TDB2::show_diff (
 
     Task after (current);
 
-    if (!prior.empty())
+    if (prior != "")
     {
       Task before (prior);
 
@@ -1084,7 +1084,7 @@ void TDB2::show_diff (
         std::string priorValue   = before.get (att.first);
         std::string currentValue = after.get  (att.first);
 
-        if (!currentValue.empty())
+        if (currentValue != "")
         {
           row = view.addRow ();
           view.set (row, 0, att.first);
@@ -1135,7 +1135,7 @@ void TDB2::show_diff (
   {
     // Create reference tasks.
     Task before;
-    if (!prior.empty())
+    if (prior != "")
       before.parse (prior);
 
     Task after (current);
@@ -1199,7 +1199,7 @@ void TDB2::show_diff (
         }
 
         // Attribute deleted.
-        else if (!before_att.empty() && after_att.empty())
+        else if (before_att != "" && after_att == "")
         {
           row = view.addRow ();
           view.set (row, 0, '-' + a + ':', color_red);
@@ -1210,7 +1210,7 @@ void TDB2::show_diff (
         }
 
         // Attribute added.
-        else if (before_att.empty() && !after_att.empty())
+        else if (before_att == "" && after_att != "")
         {
           row = view.addRow ();
           view.set (row, 0, '-' + a + ':', color_red);
@@ -1417,7 +1417,7 @@ const std::vector <Task> TDB2::children (Task& task)
 std::string TDB2::uuid (int id)
 {
   std::string result = pending.uuid (id);
-  if (result.empty())
+  if (result == "")
     result = completed.uuid (id);
 
   return result;
diff --git a/src/TLSClient.cpp b/src/TLSClient.cpp
index 4916e1e81..990a7a9d5 100644
--- a/src/TLSClient.cpp
+++ b/src/TLSClient.cpp
@@ -156,7 +156,7 @@ void TLSClient::init (
     throw format ("Bad System Trust. {1}", gnutls_strerror (ret)); // All
 #endif
 
-  if (!_ca.empty())
+  if (_ca != "")
   {
     // The gnutls_certificate_set_x509_key_file call returns number of
     // certificates parsed on success (including 0, when no certificate was
@@ -170,8 +170,8 @@ void TLSClient::init (
   }
 
   // TODO This may need 0x030111 protection.
-  if (!_cert.empty() &&
-      !_key.empty() &&
+  if (_cert != "" &&
+      _key != "" &&
       (ret = gnutls_certificate_set_x509_key_file (_credentials, _cert.c_str (), _key.c_str (), GNUTLS_X509_FMT_PEM)) < 0) // 3.1.11
     throw format ("Bad client CERT/KEY file. {1}", gnutls_strerror (ret)); // All
 
@@ -189,7 +189,7 @@ void TLSClient::init (
     throw format ("TLS client init error. {1}", gnutls_strerror (ret)); // All
 
   // Use default priorities unless overridden.
-  if (_ciphers.empty())
+  if (_ciphers == "")
     _ciphers = "NORMAL";
 
   const char *err;
diff --git a/src/Task.cpp b/src/Task.cpp
index 14a170a9c..646fc02f1 100644
--- a/src/Task.cpp
+++ b/src/Task.cpp
@@ -653,7 +653,7 @@ void Task::parseJSON (const json::object* root_obj)
   {
     // If the attribute is a recognized column.
     std::string type = Task::attributes[i.first];
-    if (!type.empty())
+    if (type != "")
     {
       // Any specified id is ignored.
       if (i.first == "id")
@@ -678,7 +678,7 @@ void Task::parseJSON (const json::object* root_obj)
         auto text = i.second->dump ();
         Lexer::dequote (text);
         Datetime d (text);
-        set (i.first, text.empty() ? "" : d.toEpochString ());
+        set (i.first, text == "" ? "" : d.toEpochString ());
       }
 
       // Tags are an array of JSON strings.
@@ -840,11 +840,11 @@ std::string Task::composeF4 () const
   {
     // Orphans have no type, treat as string.
     std::string type = Task::attributes[it.first];
-    if (type.empty())
+    if (type == "")
       type = "string";
 
     // If there is a value.
-    if (!it.second.empty())
+    if (it.second != "")
     {
       ff4 += (first ? "" : " ");
       ff4 += it.first;
@@ -883,14 +883,14 @@ std::string Task::composeJSON (bool decorate /*= false*/) const
       continue;
 
     // If value is an empty string, do not ever output it
-    if (i.second.empty())
+    if (i.second == "")
         continue;
 
     if (attributes_written)
       out << ',';
 
     std::string type = Task::attributes[i.first];
-    if (type.empty())
+    if (type == "")
       type = "string";
 
     // Date fields are written as ISO 8601.
@@ -901,7 +901,7 @@ std::string Task::composeJSON (bool decorate /*= false*/) const
           << (i.first == "modification" ? "modified" : i.first)
           << "\":\""
           // Date was deleted, do not export parsed empty string
-          << (i.second.empty() ? "" : d.toISO ())
+          << (i.second == "" ? "" : d.toISO ())
           << '"';
 
       ++attributes_written;
@@ -1124,7 +1124,7 @@ void Task::addDependency (int depid)
 {
   // Check that id is resolvable.
   std::string uuid = Context::getContext ().tdb2.pending.uuid (depid);
-  if (uuid.empty())
+  if (uuid == "")
     throw format ("Could not create a dependency on task {1} - not found.", depid);
 
   std::string depends = get ("depends");
@@ -1146,7 +1146,7 @@ void Task::addDependency (const std::string& uuid)
 
   // Store the dependency.
   std::string depends = get ("depends");
-  if (!depends.empty())
+  if (depends != "")
   {
     // Check for extant dependency.
     if (depends.find (uuid) == std::string::npos)
@@ -1193,7 +1193,7 @@ void Task::removeDependency (int id)
 {
   std::string depends = get ("depends");
   std::string uuid = Context::getContext ().tdb2.pending.uuid (id);
-  if (!uuid.empty() && depends.find (uuid) != std::string::npos)
+  if (uuid != "" && depends.find (uuid) != std::string::npos)
     removeDependency (uuid);
   else
     throw format ("Could not delete a dependency on task {1} - not found.", id);
@@ -1491,13 +1491,13 @@ void Task::substitute (
 void Task::validate (bool applyDefault /* = true */)
 {
   Task::status status = Task::pending;
-  if (!get ("status").empty())
+  if (get ("status") != "")
     status = getStatus ();
 
   // 1) Provide missing attributes where possible
   // Provide a UUID if necessary. Validate if present.
   std::string uid = get ("uuid");
-  if (has ("uuid") && !uid.empty())
+  if (has ("uuid") && uid != "")
   {
     Lexer lex (uid);
     std::string token;
@@ -1513,8 +1513,8 @@ void Task::validate (bool applyDefault /* = true */)
   if (status == Task::pending                     &&
       has ("due")                                 &&
       has ("recur")                               &&
-      (! has ("parent") || get ("parent").empty())  &&
-      (! has ("template") || get ("template").empty()))
+      (! has ("parent") || get ("parent") == "")  &&
+      (! has ("template") || get ("template") == ""))
   {
     status = Task::recurring;
   }
@@ -1532,16 +1532,16 @@ void Task::validate (bool applyDefault /* = true */)
   // Tasks with a wait: date get a special status.
   else if (status == Task::pending &&
            has ("wait")            &&
-           !get ("wait").empty())
+           get ("wait") != "")
     status = Task::waiting;
 
   // By default, tasks are pending.
-  else if (! has ("status") || get ("status").empty())
+  else if (! has ("status") || get ("status") == "")
     status = Task::pending;
 
   // Default to 'periodic' type recurrence.
   if (status == Task::recurring &&
-      (! has ("rtype") || get ("rtype").empty()))
+      (! has ("rtype") || get ("rtype") == ""))
   {
     set ("rtype", "periodic");
   }
@@ -1551,26 +1551,26 @@ void Task::validate (bool applyDefault /* = true */)
 
 #ifdef PRODUCT_TASKWARRIOR
   // Provide an entry date unless user already specified one.
-  if (! has ("entry") || get ("entry").empty())
+  if (! has ("entry") || get ("entry") == "")
     setAsNow ("entry");
 
   // Completed tasks need an end date, so inherit the entry date.
   if ((status == Task::completed || status == Task::deleted) &&
-      (! has ("end") || get ("end").empty()))
+      (! has ("end") || get ("end") == ""))
     setAsNow ("end");
 
   // Pending tasks cannot have an end date, remove if present
-  if ((status == Task::pending) && (!get ("end").empty()))
+  if ((status == Task::pending) && (get ("end") != ""))
     remove ("end");
 
   // Provide an entry date unless user already specified one.
-  if (! has ("modified") || get ("modified").empty())
+  if (! has ("modified") || get ("modified") == "")
     setAsNow ("modified");
 
-  if (applyDefault && (! has ("parent") || get ("parent").empty()))
+  if (applyDefault && (! has ("parent") || get ("parent") == ""))
   {
     // Override with default.project, if not specified.
-    if (!Task::defaultProject.empty() &&
+    if (Task::defaultProject != "" &&
         ! has ("project"))
     {
       if (Context::getContext ().columns["project"]->validate (Task::defaultProject))
@@ -1578,7 +1578,7 @@ void Task::validate (bool applyDefault /* = true */)
     }
 
     // Override with default.due, if not specified.
-    if (!Task::defaultDue.empty() &&
+    if (Task::defaultDue != "" &&
         ! has ("due"))
     {
       if (Context::getContext ().columns["due"]->validate (Task::defaultDue))
@@ -1592,7 +1592,7 @@ void Task::validate (bool applyDefault /* = true */)
     }
 
     // Override with default.scheduled, if not specified.
-    if (!Task::defaultScheduled.empty() &&
+    if (Task::defaultScheduled != "" &&
         ! has ("scheduled"))
     {
       if (Context::getContext ().columns["scheduled"]->validate (Task::defaultScheduled))
@@ -1620,7 +1620,7 @@ void Task::validate (bool applyDefault /* = true */)
       }
     }
 
-    if (!udas.empty())
+    if (udas.size ())
     {
       // For each of those, setup the default value on the task now,
       // of course only if we don't have one on the command line already
@@ -1629,7 +1629,7 @@ void Task::validate (bool applyDefault /* = true */)
         std::string defVal= Context::getContext ().config.get ("uda." + uda + ".default");
 
         // If the default is empty, or we already have a value, skip it
-        if (!defVal.empty() && get (uda).empty())
+        if (defVal != "" && get (uda) == "")
           set (uda, defVal);
       }
     }
@@ -1652,18 +1652,18 @@ void Task::validate (bool applyDefault /* = true */)
   // There is no fixing a missing description.
   if (! has ("description"))
     throw std::string ("A task must have a description.");
-  else if (get ("description").empty())
+  else if (get ("description") == "")
     throw std::string ("Cannot add a task that is blank.");
 
   // Cannot have a recur frequency with no due date - when would it recur?
-  if (has ("recur") && (! has ("due") || get ("due").empty()))
+  if (has ("recur") && (! has ("due") || get ("due") == ""))
     throw std::string ("A recurring task must also have a 'due' date.");
 
   // Recur durations must be valid.
   if (has ("recur"))
   {
     std::string value = get ("recur");
-    if (!value.empty())
+    if (value != "")
     {
       Duration p;
       std::string::size_type i = 0;
@@ -2074,13 +2074,13 @@ void Task::modify (modType type, bool text_required /* = false */)
         // 'value' requires eval.
         std::string name  = a.attribute ("canonical");
         std::string value = a.attribute ("value");
-        if (value.empty()     ||
+        if (value == ""     ||
             value == "''"   ||
             value == "\"\"")
         {
           // ::composeF4 will skip if the value is blank, but the presence of
           // the attribute will prevent ::validate from applying defaults.
-          if ((has (name) && !get (name).empty()) ||
+          if ((has (name) && get (name) != "") ||
               (name == "due"       && Context::getContext ().config.has ("default.due")) ||
               (name == "scheduled" && Context::getContext ().config.has ("default.scheduled")) ||
               (name == "project"   && Context::getContext ().config.has ("default.project")))
@@ -2155,7 +2155,7 @@ void Task::modify (modType type, bool text_required /* = false */)
       // Unknown args are accumulated as though they were WORDs.
       else
       {
-        if (!text.empty())
+        if (text != "")
           text += ' ';
         text += a.attribute ("raw");
       }
@@ -2164,7 +2164,7 @@ void Task::modify (modType type, bool text_required /* = false */)
 
   // Task::modType determines what happens to the WORD arguments, if there are
   //  any.
-  if (!text.empty())
+  if (text != "")
   {
     Lexer::dequote (text);
 
diff --git a/src/Variant.cpp b/src/Variant.cpp
index 133320f55..c9cb54020 100644
--- a/src/Variant.cpp
+++ b/src/Variant.cpp
@@ -1900,7 +1900,7 @@ void Variant::cast (const enum type new_type)
           break;
         }
 
-        if (!dateFormat.empty())
+        if (dateFormat != "")
         {
           _date = Datetime (_string, dateFormat).toEpoch ();
           break;
@@ -1961,7 +1961,7 @@ bool Variant::trivial () const
 {
   return (_type == type_integer  && _integer  == 0)   ||
          (_type == type_real     && _real     == 0.0) ||
-         (_type == type_string   && _string.empty())  ||
+         (_type == type_string   && _string   == "")  ||
          (_type == type_date     && _date     == 0)   ||
          (_type == type_duration && _duration == 0);
 }
diff --git a/src/ViewTask.cpp b/src/ViewTask.cpp
index b39057e1f..29ef5be75 100644
--- a/src/ViewTask.cpp
+++ b/src/ViewTask.cpp
@@ -327,7 +327,7 @@ std::string ViewTask::render (std::vector <Task>& data, std::vector <int>& seque
     // Listing breaks are simply blank lines inserted when a column value
     // changes.
     if (s > 0 &&
-        !_breaks.empty())
+        _breaks.size () > 0)
     {
       for (auto& b : _breaks)
       {
diff --git a/src/dependency.cpp b/src/dependency.cpp
index 26fdf013a..80e1cb874 100644
--- a/src/dependency.cpp
+++ b/src/dependency.cpp
@@ -58,7 +58,7 @@ std::vector <Task> dependencyGetBlocking (const Task& task)
   auto depends = task.get ("depends");
 
   std::vector <Task> blocking;
-  if (!depends.empty())
+  if (depends != "")
     for (auto& it : Context::getContext ().tdb2.pending.get_tasks ())
       if (it.getStatus () != Task::completed &&
           it.getStatus () != Task::deleted   &&
@@ -153,7 +153,7 @@ void dependencyChainOnComplete (Task& task)
   auto blocking = dependencyGetBlocking (task);
 
   // If the task is anything but the tail end of a dependency chain.
-  if (!blocking.empty())
+  if (blocking.size ())
   {
     auto blocked = dependencyGetBlocked (task);
 
@@ -168,7 +168,7 @@ void dependencyChainOnComplete (Task& task)
     }
 
     // If there are both blocking and blocked tasks, the chain is broken.
-    if (!blocked.empty())
+    if (blocked.size ())
     {
       if (Context::getContext ().config.getBoolean ("dependency.reminder"))
       {
@@ -211,7 +211,7 @@ void dependencyChainOnStart (Task& task)
 
     // If the task is anything but the tail end of a dependency chain, nag about
     // broken chain.
-    if (!blocking.empty())
+    if (blocking.size ())
     {
       std::cout << format (STRING_DEPEND_BLOCKED, task.identifier ())
                 << '\n';
diff --git a/src/feedback.cpp b/src/feedback.cpp
index 6cd63e7d2..0e1d793c3 100644
--- a/src/feedback.cpp
+++ b/src/feedback.cpp
@@ -208,8 +208,8 @@ std::string taskInfoDifferences (
     if (name              != "uuid" &&
         name              != "modified" &&
         before.get (name) != after.get (name) &&
-        !before.get (name).empty() &&
-        !after.get (name).empty())
+        before.get (name) != "" &&
+        after.get (name)  != "")
     {
       if (name == "depends")
       {
@@ -245,10 +245,10 @@ std::string renderAttribute (const std::string& name, const std::string& value,
     Column* col = Context::getContext ().columns[name];
     if (col                    &&
         col->type () == "date" &&
-        !value.empty())
+        value != "")
     {
       Datetime d ((time_t)strtol (value.c_str (), nullptr, 10));
-      if (format.empty())
+      if (format == "")
         return d.toString (Context::getContext ().config.get ("dateformat"));
 
       return d.toString (format);
@@ -379,7 +379,7 @@ void feedback_unblocked (const Task& task)
     for (auto& i : blocked)
     {
       auto blocking = dependencyGetBlocking (i);
-      if (blocking.empty())
+      if (blocking.size () == 0)
       {
         if (i.id)
           std::cout << format ("Unblocked {1} '{2}'.",
@@ -402,7 +402,7 @@ void feedback_unblocked (const Task& task)
 ///////////////////////////////////////////////////////////////////////////////
 void feedback_backlog ()
 {
-  if (!Context::getContext ().config.get ("taskd.server").empty() &&
+  if (Context::getContext ().config.get ("taskd.server") != "" &&
       Context::getContext ().verbose ("sync"))
   {
     int count = 0;
@@ -423,7 +423,7 @@ std::string onProjectChange (Task& task, bool scope /* = true */)
   std::stringstream msg;
   std::string project = task.get ("project");
 
-  if (!project.empty())
+  if (project != "")
   {
     if (scope)
       msg << format ("The project '{1}' has changed.", project)
diff --git a/src/legacy.cpp b/src/legacy.cpp
index 83438e67e..9ed440e78 100644
--- a/src/legacy.cpp
+++ b/src/legacy.cpp
@@ -116,7 +116,7 @@ std::string legacyCheckForDeprecatedVariables ()
   }
 
   std::stringstream out;
-  if (!deprecated.empty())
+  if (deprecated.size ())
   {
     out << "Your .taskrc file contains variables that are deprecated:\n";
 
@@ -149,7 +149,7 @@ std::string legacyCheckForDeprecatedColumns ()
   std::stringstream out;
   out << "\n";
 
-  if (!deprecated.empty())
+  if (deprecated.size ())
   {
     out << "Your .taskrc file contains reports with deprecated columns.  Please check for entry_time, start_time or end_time in:\n";
 
diff --git a/src/nag.cpp b/src/nag.cpp
index 0c905918c..cf69db8c6 100644
--- a/src/nag.cpp
+++ b/src/nag.cpp
@@ -41,7 +41,7 @@ bool nag (Task& task)
     return false;
 
   auto msg = Context::getContext ().config.get ("nag");
-  if (!msg.empty())
+  if (msg != "")
   {
     // Scan all pending, non-recurring tasks.
     auto pending = Context::getContext ().tdb2.pending.get_tasks ();
diff --git a/src/recur.cpp b/src/recur.cpp
index 479b1e470..c14539c99 100644
--- a/src/recur.cpp
+++ b/src/recur.cpp
@@ -155,7 +155,7 @@ bool generateDueDates (Task& parent, std::vector <Datetime>& allDue)
 
   bool specificEnd = false;
   Datetime until;
-  if (!parent.get ("until").empty())
+  if (parent.get ("until") != "")
   {
     until = Datetime (parent.get ("until"));
     specificEnd = true;
@@ -371,7 +371,7 @@ void updateRecurrenceMask (Task& task)
   auto uuid = task.get ("parent");
   Task parent;
 
-  if (!uuid.empty() &&
+  if (uuid != "" &&
       Context::getContext ().tdb2.get (uuid, parent))
   {
     unsigned int index = strtol (task.get ("imask").c_str (), nullptr, 10);
diff --git a/src/recur2.cpp b/src/recur2.cpp
index 4c22d7142..f9ca27075 100644
--- a/src/recur2.cpp
+++ b/src/recur2.cpp
@@ -279,7 +279,7 @@ static std::vector <Datetime> generateAllDueDates (const Task& templateTask)
 
   bool end_in_sight = false;
   Datetime until;
-  if (!templateTask.get ("until").empty())
+  if (templateTask.get ("until") != "")
   {
     until = Datetime (templateTask.get ("until"));
     end_in_sight = true;
@@ -296,7 +296,7 @@ static std::vector <Datetime> generateAllDueDates (const Task& templateTask)
     Datetime nextDue = generateNextDueDate (due, recur, lastN);
 
     // TODO Safety.
-    if (!dueDates.empty() && dueDates.back () == nextDue)
+    if (dueDates.size () && dueDates.back () == nextDue)
       break;
 
     // If nextDue > until, it means there are no more tasks to generate, so
diff --git a/src/sort.cpp b/src/sort.cpp
index 6cba01291..8fa6e50be 100644
--- a/src/sort.cpp
+++ b/src/sort.cpp
@@ -55,7 +55,7 @@ void sort_tasks (
   global_keys = split (keys, ',');
 
   // Only sort if necessary.
-  if (!order.empty())
+  if (order.size ())
     std::stable_sort (order.begin (), order.end (), sort_compare);
 
   Context::getContext ().time_sort_us += timer.total_us ();
@@ -68,7 +68,7 @@ void sort_projects (
   for (auto& project : allProjects)
   {
     const std::vector <std::string> parents = extractParents (project.first);
-    if (!parents.empty())
+    if (parents.size ())
     {
       // if parents exist: store iterator position of last parent
       std::list <std::pair <std::string, int>>::iterator parent_pos;
@@ -184,10 +184,10 @@ static bool sort_compare (int left, int right)
       auto left_string  = (*global_data)[left].get_ref  (field);
       auto right_string = (*global_data)[right].get_ref (field);
 
-      if (!left_string.empty() && right_string.empty())
+      if (left_string != "" && right_string == "")
         return true;
 
-      if (left_string.empty() && !right_string.empty())
+      if (left_string == "" && right_string != "")
         return false;
 
       if (left_string == right_string)
@@ -207,10 +207,10 @@ static bool sort_compare (int left, int right)
       if (left_string == right_string)
         continue;
 
-      if (left_string.empty() && !right_string.empty())
+      if (left_string == "" && right_string != "")
         return ascending;
 
-      if (!left_string.empty() && right_string.empty())
+      if (left_string != "" && right_string == "")
         return !ascending;
 
       // Sort on the first dependency.
@@ -274,9 +274,9 @@ static bool sort_compare (int left, int right)
         else
         {
           // Empty values are unconditionally last, if no custom order was specified.
-          if (left_string.empty())
+          if (left_string == "")
             return false;
-          else if (right_string.empty())
+          else if (right_string == "")
             return true;
 
           return ascending ? (left_string < right_string)
@@ -289,10 +289,10 @@ static bool sort_compare (int left, int right)
         auto left_string  = (*global_data)[left].get_ref  (field);
         auto right_string = (*global_data)[right].get_ref (field);
 
-        if (!left_string.empty() && right_string.empty())
+        if (left_string != "" && right_string == "")
           return true;
 
-        if (left_string.empty() && !right_string.empty())
+        if (left_string == "" && right_string != "")
           return false;
 
         if (left_string == right_string)