That's something I've run into myself. I just recently finished the Enterprise Lego set, and it was fun to build... but I doubt if I will ever take it apart and rebuild it. There were 30 bags in that set, and I don't much fancy the prospect of trying to sift through all the pieces at once rebuilding the thing.
Finish a set? Lego Enterprise? Don't want to build anything else with it?
I see that the Lego I remember and the Lego of today are two vastly different things.