What age used RV to buy for newbie?

In our experience, the fridge, roof AC unit, converter charger , fresh water pump, house and starting batteries needed replacement at around 10 years old. I often advise people to buy used rigs around 3-5 years old but spend the money to have them inspected by a pro truck mechanic and an independent RV repair service. Get a written list of repairs and replacements needed including estimated parts and labor costs. Tires older than 5 years old are often unsafe regardless of appearance or tread depth. The entire brake and engine cooling system should be serviced as needed. Your rig's batteries, converter/charger and plumbing must be in good working condition. Don't buy a rig with mold smell or water stains in ceiling, roof repairs are very expensive. Expect to spend some big bucks the first year and put money aside for repairs and miscellaneous costs of ownership including emergency road service, DMV and insurance and lot storage cost, if required. RV ownership and use is an expensive hobby pastime,
worth doing if you and your mate BOTH really enjoy it and want to do it with your kids. Expect kids to lose interest as they grow up. We prefer rigs at least 27 feet long with rear bedroom and storage room. Most shorter rigs have less comfortable sleeping in the overhead bunk and convertible dinette and clutter in the aisle and in shower stall.