our coach is 10 yrs old, actually 11, w/ more than 100k miles on it & over 3k hours on the gen....ours is not some broken-down POS. We maintain it well & rarely if ever have any issue enough to have to work on it in any RV park.
We have minor stuff occasionally - how water heater switch went bad (4 dollar part) & i once had a GFCI outlet (in one of my basement storage bins) fail....no big deal.
I've seen (and helped) folks w/ newer units replace melted power cords or busted hose fittings...piece parts wear out more frequently from LACK of use than over use.