in my experience (4 years) re using shrink wrap can be done successfully when careful, must be done on same or VERY similar boat, and depens how far down the hull sides you want to cover...

we used to use the wrap from the sport cruisers and yachts coming in to wrap up the ski boats.. the top and deck portions didnt have that much heat applied to them in the first place so its like virgin material..

I see several people reuse it at marinas around me. It's just not as snug fitting but it works