Right now on patron records you need an expiration date but not all libraries use that type of function and the expiration date actually gets in their way. It would be nice if you could choose if your library cares about expiration dates.
This would be helpful.
We recently noticed some issues with missing expiration dates - it affected the due date calculations. This might be due to the fact that Koha tries to set the due date before the patron expires, but if we were to make the expiration date optional, this is something that would need a closer look.