Kept my RV inside my shop / garage / farm maintainence building for years now. Shop is air conditioned and has it's own 200 amp service and I have a 50 amp RV plug next to the unit.
The last indefinitely when kept out of the weather. Last one I had (and sold) was 15 years old and looked new, had no leaks and nice thing about keeping them inside, they are ready to go quickly.
Winters are tough here and my RV is snug as a bug in a rug inside with my pickup truck.
Have my own dump station too and water hookup if I require water.
In the winter, when I'm working on farm tractors, I use the RV to make coffee and keep the fridge running to keep my creamer and lunch meat cold so I can make a sandwich and have a cold pop or cup of coffee without going in the house.
My shop also has a bathroom and PEX in floor heat.
