QUOTE(pianotuna @ Aug 8 2010, 02:56 PM)
RV covers are a great way to destroy the finish on an RV. The wind causes it to shift and grind away at the surface.
That is exactly right. I've restored vehicles worth more than a lot of motor homes and occasionally I would leave them outside. It was better to expose them to the elements than to ever cover them up.
When the cover is new, it is fairly clean on the inside. There is no way to take the cover off without some dirt getting on the inside surfaces. Any dirt on the inside surface, which is a cumulative amount of dirt, will act like sand paper on the surfaces of the rig when the wind blows it. The wind blowing against the cover will cause it to billow somewhat and that just allows more dirt to blow under it.
Besides that, I have also heard of owners getting hurt while trying to cover or uncover their coach. The cover is heavy, the coach is high, and all it takes is one misstep to ruin your day. Just keep the coach washed occasionally, with a yearly coat of a good quality wax and the paint will last a long time.
I should add that on another forum that I go to, an owner had a problem with the cover sticking to the roof coating on his coach. He ended up damaging the roof trying to get the cover off. Apparently the heat was too much and it caused the roof coating to soften and the cover to stick.