My thoughts are that when I'm unable to do the fairly simple repairs most of the problems require is the day I hang up the RV and go sit in my living and wait to die.
Growing up I've watched people wither away as they convinced themselves they can't do things anymore because they are 65, 75 or 85 whatever age.
I prefer to keep on doing even if it might take a little longer or might be a bit more challenging physically. Sure I might get a little more sore as I age, might take me a little while longer to fiddle and diddle with things but I'm active, it keeps my brain active and my body moving. That really is half the battle right there, just staying active and not withering away listening to my arteries harden as I sit inside watching the boob tube.