I don't full time but I rarely use my generator. If buying a new camper I don't think I'd bother having one. A good inverter and battery bank will run the microwave or toatster for a minute or too. If I want air conditioning I go to a CG that has electric. Most campgrounds won't let you run a generator around the clock for air conditioning anyway.
My generator is 13 years old. I think it has around 80 hours on it. The vast majority of that time was powering my house during power outages and just the normal "maintenance" running your supposed to do every once in a while.