Add a notification to ArcGIS Online to indicate that additional credits purchased are about to expire after 2 years. Maybe give a 1 month or 2 month notice. Possibly an email notification as well.
Background: Purchased 1000 additional credits 2 years ago since it seems like we would be using AGO a lot. We ended up not using as many credits as we thought we would on some projects/data storage. I didn't realize there was an expiration date on digital credits. There were no notifications that they were about to expire last week and then had 600 credits disappear overnight. Had I know or received some sort of notification, it would have been nice to test out some features of ArcGIS online with those expiring credits before they all disappeared.