diff --git a/README.md b/README.md
index 3eda618..b92078f 100644
--- a/README.md
+++ b/README.md
@@ -37,8 +37,8 @@ Optional environment variables:
 - `ALBUM_SEPARATOR`: Separator for `relative` mode; defaults to ` - `
 - `PAGE_SIZE`: Immich search page size; defaults to `1000`
 - `DRY_RUN`: Set to `true` to log planned work without changing albums
-- `SYNC_INTERVAL_SECONDS`: Delay between runs; `0` runs once and exits.
-  Docker Compose defaults to `1800` seconds (30 minutes)
+- `SYNC_INTERVAL_SECONDS`: Delay between runs; defaults to `1800` seconds
+  (30 minutes). Set it to `0` for a single run
 
 Run the script after Immich has scanned the external library:
 
diff --git a/src/main.py b/src/main.py
index b3945b7..2e577d4 100644
--- a/src/main.py
+++ b/src/main.py
@@ -33,7 +33,7 @@ ALBUM_SEPARATOR = os.environ.get("ALBUM_SEPARATOR", " - ")
 PAGE_SIZE = int(os.environ.get("PAGE_SIZE", "1000"))
 DRY_RUN = os.environ.get("DRY_RUN", "false").lower() == "true"
 SYNC_INTERVAL_SECONDS = int(
-    os.environ.get("SYNC_INTERVAL_SECONDS", "0")
+    os.environ.get("SYNC_INTERVAL_SECONDS", "1800")
 )
 
 logging.basicConfig(
diff --git a/tests/test_main.py b/tests/test_main.py
index 7f24871..4abd27d 100644
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -142,6 +142,10 @@ class SynchronizationTests(unittest.TestCase):
             album_sync,
             "ALBUM_MODE",
             "root",
+        ), patch.object(
+            album_sync,
+            "SYNC_INTERVAL_SECONDS",
+            0,
         ), patch.object(
             album_sync,
             "check_configuration",