Dear Ana,
Cleanup activity is important as it is related to maintenance and I would recommend you for monthly recurrence.
If you have never performed the activity in a while follow the below steps:
1. Go to Analytics Users & Assets.
2. Exports the list using CSV.
3. Check for the access created date and last analytics access. This will give a fair idea of the user's engagement.
4. Try to remove the mails IDs, not with your organization at present, and also the people who never used Adobe Analytics for the past 6 months. Make sure that you transfer the assets to you before deleting someone's access.
5. Compare the same with Admin Console and make sure that you have proper synchronization.
Thanks & Regards,
Arun.