The only time when I've had the clutch power loosen on a LEGO set was when the pieces were cracked. If they aren't cracked, you shouldn't worry too much. A while back I got the Green Grocer (while it was still available for retail price) and built it. I eventually thought of all the great things I could create with the pieces and took it apart and built a few houses. About a year later at Christmas, I was expecting to receive another modular and wanted to put them together, so I built it again. I never had the pieces lose clutch power, and it is currently being displayed with all my other modulars. As long as you have your sets out of direct sunlight and do not get your pieces dirty, than I would not worry about damage to the set.