The longevity of an RV is mainly determined by how it was maintained by the previous owners. The previous owner could have addressed items that failed and the coach may now provide years of trouble free service. The alternative is that the previous owners ignored minor problems and the next owner will have to take care of them. That is the problem with buying any new OR used coach. They are complex vehicles and there is a lot to go wrong.
Most of us focus on what lies ahead in our travels instead of what MAY be future problems that will interrupt our next trip.