Mine is 10 years old this year and see no reason why it will not go another 10-15 without any major repairs which should do it for me. That said, my role model is a couple from SC that bought a new Beaver DP at 84 and drove it to OR in three days to attend a Beaver rally. She was limping from having broken a leg snow skiing that winter.
Nine years ago the only way to get four slides was buying one that was fairly new. Other than full wall slides there has not been any major changes in this area in the last 10 years. Assuming a fiberglass roof (no leaks) and stored under cover MHs could well last 50 years... like Airstream TT. My airplane is 35 years old and other than a upgraded radio I have not spent any major money on it in the 33 years I've owned it. Storing our toys inside is probably the best thing we can do for them.
