I'm one of Ron's "serious about PM" types, and I found that the probability of things breaking is directly proportional to the number of times you use it. I went through this Sahara last spring and summer getting ready for the winter trip. Anything that was questionable was fixed or replaced. I figured I had everything covered. Then we started full timing and stuff that was on the edge started failing. Nothing big, but things that required a trip to the RV parts store, and if I was not able to do the work myself, would have interrupted the trip waiting for an RV repair person to address.
When buying used, you can expect to pay at least 10% of the purchase price the first year, fixing things that were deferred and making it your own. After that, the usability of the rig depends on the initial quality.
