Problem is that RVs can get nasty just by sitting around, either on a dealer lot, a wholesale lot, or at the previous owner's place.
I have found that even in Texas where the weather conditions don't get that extreme, every 3-6 months, a rig needs some TLC, be it inflating tires, venting it out, making sure appliances work, getting the detritus out of flues, and other basic maintenance tasks. Cosmetic things are important too like washing the rig, oiling hinges, locks, and other moving parts, and so on.
Of course, there is the most important thing of all... checking the roof every few months. One imperceptible crack in the caulking, and the rig is destroyed.
Worst thing that can happen to a rig is that it sits without being at least inspected twice a year.