How old is too old, subjective question but I want opinions

Remember your rig should have a rubber roof on it. It should be warranty for 10 years, and the lifespan should be around 20. To have someone replace that roof will be $3-6,000 depending. Your roof is currently 16 years old. If you're OK with that then keep it, if not then move on.

The last thing you want is a leak which goes undetected. That will kill a RV at that age.