diff --git a/cli/src/invocation/mod.rs b/cli/src/invocation/mod.rs
index d7bcaef0a..9b9d7029c 100644
--- a/cli/src/invocation/mod.rs
+++ b/cli/src/invocation/mod.rs
@@ -106,15 +106,25 @@ fn get_replica(settings: &Config) -> Fallible<Replica> {
 
 /// Get the server for this invocation
 fn get_server(settings: &Config) -> Fallible<Box<dyn server::Server>> {
-    let client_id = settings.get_str("server_client_id")?;
-    let client_id = Uuid::parse_str(&client_id)?;
-    let origin = settings.get_str("server_origin")?;
-    log::debug!("Using sync-server with origin {}", origin);
-    log::debug!("Sync client ID: {}", client_id);
-    Ok(server::from_config(ServerConfig::Remote {
-        origin,
-        client_id,
-    })?)
+    // if server_client_id and server_origin are both set, use
+    // the remote server
+    if let (Ok(client_id), Ok(origin)) = (
+        settings.get_str("server_client_id"),
+        settings.get_str("server_origin"),
+    ) {
+        let client_id = Uuid::parse_str(&client_id)?;
+
+        log::debug!("Using sync-server with origin {}", origin);
+        log::debug!("Sync client ID: {}", client_id);
+        Ok(server::from_config(ServerConfig::Remote {
+            origin,
+            client_id,
+        })?)
+    } else {
+        let server_dir = settings.get_str("server_dir")?.into();
+        log::debug!("Using local sync-server at `{:?}`", server_dir);
+        Ok(server::from_config(ServerConfig::Local { server_dir })?)
+    }
 }
 
 /// Get a WriteColor implementation based on whether the output is a tty.
diff --git a/cli/src/settings.rs b/cli/src/settings.rs
index 02e554c76..4d59b00be 100644
--- a/cli/src/settings.rs
+++ b/cli/src/settings.rs
@@ -7,12 +7,21 @@ pub(crate) fn read_settings() -> Fallible<Config> {
     let mut settings = Config::default();
 
     // set up defaults
-    if let Some(mut dir) = dirs::data_local_dir() {
-        dir.push("taskchampion");
+    if let Some(dir) = dirs::data_local_dir() {
+        let mut tc_dir = dir.clone();
+        tc_dir.push("taskchampion");
         settings.set_default(
             "data_dir",
             // the config crate does not support non-string paths
-            dir.to_str().expect("data_local_dir is not utf-8"),
+            tc_dir.to_str().expect("data_local_dir is not utf-8"),
+        )?;
+
+        let mut server_dir = dir;
+        server_dir.push("taskchampion-sync-server");
+        settings.set_default(
+            "server_dir",
+            // the config crate does not support non-string paths
+            server_dir.to_str().expect("data_local_dir is not utf-8"),
         )?;
     }
 
diff --git a/docs/src/usage.md b/docs/src/usage.md
index 84ee5626c..5ddc60c91 100644
--- a/docs/src/usage.md
+++ b/docs/src/usage.md
@@ -17,15 +17,33 @@ On OS X, it's `~/Library/Preferences`.
 On Windows, it's `AppData/Roaming` in your home directory.
 The path can be overridden by setting `$TASKCHAMPION_CONFIG`.
 
-Individual configuration parameters can be overridden by environemnt variables, converted to upper-case and prefixed with `TASKCHAMPION_`, e.g., `TASKCHAMPION_DATA_DIR`.
+Individual configuration parameters can be overridden by environment variables, converted to upper-case and prefixed with `TASKCHAMPION_`, e.g., `TASKCHAMPION_DATA_DIR`.
 Nested configuration parameters cannot be overridden by environment variables.
 
 The following configuration parameters are available:
 
 * `data_dir` - path to a directory containing the replica's task data (which will be created if necessary).
-  Default: `taskchampion` in the local data directory
-* `server_origin` - Origin of the taskchampion sync server, e.g., `https://taskchampion.example.com`
+  Default: `taskchampion` in the local data directory.
+* `server_dir` - path to a directory containing the local server's data.
+  This is only used if `server_origin` or `server_client_id` are not set.
+  Default: `taskchampion-sync-server` in the local data directory.
+* `server_origin` - Origin of the TaskChampion sync server, e.g., `https://taskchampion.example.com`.
+  If not set, then sync is done to a local server.
 * `server_client_id` -  Client ID to identify this replica to the sync server (a UUID)
+  If not set, then sync is done to a local server.
+
+### Synchronization
+
+A TaskChampion replica "synchronizes" its local task database with other replicas via a sync server.
+This operation is triggered by running `task sync`.
+Typically this runs frequently in a cron task.
+The operation is quick, especially if no changes have occurred.
+
+The replica expects to be synchronized frequently, even if no server is involved.
+Without periodic syncs, the storage space used for the task database will grow quickly, and performance will suffer.
+
+By default, TaskChampion syncs to a "local server", as specified by the `server_dir` configuration parameter.
+It is possible to switch to a remote server later by setting `server_origin` and `server_client_id` appropriately.
 
 ## `taskchampion-sync-server`