It is very important that it is performed every day:
Running an Integrity CheckIntegrity checks verify and maintain data integrity on the deduplication store. The output of an integrity check is a checkpoint. By default, VDP runs an integrity check every day during the maintenance window. In addition, you can start the integrity check manually.CAUTIONIf the VDP appliance displays an alarm that the last valid integrity check failed or is out of date, run a manual integrity check. If you allow for the VDP appliance to continue to make backups while the integrity check is out of date, you are risking losing potential backup data if a rollback to the last validated checkpoint is ever required.
Read the attached document
Can I change maintenance window ?
You'd be far better off dumping VDP for something else that is not only half-way decent but also modern and supported, none of which VDP is.