The card itself has a years-long expiration date, and you’re right that there’s a formal process for them to be exchanged (at a machine, at a booth, or by mailing them in).

But OP is referring to a separate timeline: there’s a 10-trip JFK-AirTrain pass “product” that expires within 30 days. After that, the card continues to work like any other Metro Card but the pass doesn’t.