I misplaced my registation card quite some time ago, though I don’t recall them asking to see it when I voted in 2004.
Does your registration expire? Is it something like a drivers license or car registration that you need to get renewed?
It varies by jurisdiction. In my county if you fail to vote for . . . I think it is five years, might be 8, your name is removed from the registration lists. You can be re-registered at any library, fire house, or a few other places.
Tris