I just sold the pin I've had the longest at the show over the weekend. I'd almost say it was bittersweet. I had played it out, but I'll still miss it.
There is no such thing as a keeper. Eventually it hits the point where it isn't getting played enough to justify the space. And when that hits, out they go. I have a gameroom, not a museum. I think that keeps things fresh. I have a list of games I want to add, and I already know exactly what is going in that vacant spot, and the one after that.