We were there over Thanksgiving, and there were big signs up saying that these mugs were for the Fall of 2001 only, which I believe differ from other resorts.
It may be different in regards to non
DVC resorts, but when we stayed at the Poly and at AS, the mugs did not have a year on them, and could be reused at any time. I saw people being told that they could not use previously purchased mugs, and they were obviously not happy.
We did buy the mugs, but didn't get as much value out of them as we had at the other resorts mentioned, due to the fact, with the kitchen we purchased drinks for our room, whereas earlier, we always went to the resort drink counter to get all drinks. What was nice, though was for cocktails at the pool. We bought beer and wine coolers, and brought a little collapsible cooler so every afternoon, we filled this up to bring to the pool or beach and it saved us a ton of money on drinks, except for the many times, I wanted a VB daily specialty drink instead, lol.