I experimented with trying to reload relatively old MetroCards at a kiosk. The first attempt was using a card that expires on 6/30/2019; the message I received was something like "Less than 21 days until expiration; card not eligible for reload." I then used a card that expired on 8/30/2019 and was able to put a 7-Day pass on it. I wish I had a 7/30/2019 card handy, as I am pretty sure I once put a soon-to-expire card in a kiosk, loaded it, and got a fresh card with a longer expiration date back.