I haven't read all the posts in the thread, but I wanted to comment anyway. I really love long term feedback when people are gracious and give it to me. I haven't gone back and looked on my exchanges to see what the time factor is, but several people have given me an update by PM or in threads where their reading is. It's very much appreciated. The ones on the Reading Exchange forum would be within the last 6 or so months, I think, but in real life, I've also gotten updated as much as two years on from the reading.
I don't remember most readings once they're done. I remember that I've read for someone but I don't remember the details. I've seen other readers say the same. I think it's supposed to be that way. It's always nice, though, and I appreciate it a lot when someone comes back to update me. I think it would be neat if it were a tradition here on AT to get long-term feedback in the exchange forum, but it's probably not feasible. It's not something that should be required but it would be nice if people did it more.