In GENERAL terms, I've found that RVs like to be used. They generally age much more gracefully if they're in use, have good and regular maintenance and are of good quality when manufactured. Leave them sit for months on end and gremlins begin to appear and will often appear all at once (since you're not keeping up with maintenance during months of not using them). If you're using them you would be more likely to fix those little things as they present themselves and thus they don't at least SEEM to be aging as quickly.
Good luck and have lots of fun / Skip