Update replace-an-expiring-client-secret-in-a-sharepoint-add-in.md

added a recommended schedule

Author: westleyMS

docs/sp-add-ins/replace-an-expiring-client-secret-in-a-sharepoint-add-in.md

@@ -13,6 +13,12 @@ Client secrets for SharePoint Add-ins that are registered by using the AppRegNew
 > [!NOTE]
 > This article is about SharePoint Add-ins that are distributed through an organization catalog and registered with the AppRegNew.aspx page. If the add-in is registered on the Seller Dashboard, see [Create or update client IDs and secrets in the Seller Dashboard](/office/dev/store/create-or-update-client-ids-and-secrets).
 
+## Recommended maintenance schedule
+We recommend to create new secrets a minimum of 30 days before they expire. This gives you a month of time before the old credentials expire.
+We recommend to only remove secrets a minimum of 7 days after expiration, provided you have removed them from the application configuration.
+Removing an expired secret from ACS before you remove it from the application configuration will cause errors.
+
+
 ## Prerequisites
 
 Ensure the following before you begin: