diff --git a/Civi/Api4/Action/ContactCategory/Sync.php b/Civi/Api4/Action/ContactCategory/Sync.php
index 77bcd01..8fdee0f 100644
--- a/Civi/Api4/Action/ContactCategory/Sync.php
+++ b/Civi/Api4/Action/ContactCategory/Sync.php
@@ -161,8 +161,9 @@ class Sync extends \Civi\Api4\Generic\AbstractAction {
     $summary['memory_use'] = @round($_ / pow(1024, ($i = floor(log($_, 1024)))), 2) . ' ' . ['b', 'kb', 'mb', 'gb', 'tb', 'pb'][$i];
     $result->exchangeArray($summary);
 
-    // Limit to running every 6 hours.
-    $settings['updateAfter'] = time() + 60 * 60 * 6;
+    // Limit to running every 24 hours; we actually want it to be stable within one day.
+    // Schedule for 3am to avoid busy times and DST.
+    $settings['updateAfter'] = strtotime('tomorrow + 180 minutes');
     Setting::set(FALSE)
       ->addValue('contact_categories', $settings)
       ->execute();