the RV should be stored (not used) out of the sun and rain.
It's hard to overstate the importance of this. Sure, not everyone has room for a cover, but I see plenty of folks who spend 6 figures for a rig, but won't spend 6 thousand to protect it. If a rig springs a leak and is exposed constantly, the damage is ongoing. With a cover you can catch it early and save the situation. As a buyer, look first to sellers that have their rig covered, and these folks probably also inspect regularly cause they care. The average bill for damage to an overhead cab leak is $7000, ironically more than the cover they should have bought. The new one piece overhead is a good improvement, but the joint where it meets the roof needs an inspection yearly. Also the overhead cab lights. I'm sure there are plenty of uncovered C's that are fine, but they only come with owners who care and stay on top of it. As a side note, there is a RV salesman, when taking a C in trade, asks the owner right of the bat "where is your leak?".