Reviewing changes can be useful for troubleshooting, particularly for unexpected delivery patterns. For most items, the change history displays what attribute changed, the former and new values (for example from "Paused" to "enabled"), the user who made the change, and the date and time the change was made.
In some cases, the Ad Manager itself makes changes. These changes often result from new features or product changes. Changes initiated by the Ad Manager keep your system healthy and ensure that your campaigns run smoothly.