There is always a license which might expire one day, and almost everyone had the experience with forgetting it - in worse case even getting a financial penalty from photographer or stockphoto agency.
There are 4 license expiring warnings in our system :
1) 14 days before a license expires the owner and the editor gets "expiration warning" email, so he has enough time to react or ignore this warning.
2) There is one more "expiry warning" on the day of the license expiration
3) In the Owners(Admin) DASHBOARD, LICENSE CALENDAR & LICENSE MANAGER is listed when the next license might expire
4) Visual WARNING-SIGN in every preview and file-detail is placed and cannot be overseen