Just because someone lives to age 83, won't mean they can still ride at that age. There are no guarantees no matter what you do. So all I can do is think ahead a little bit, and try and pick a fit that's best suited for me. Some might want to find a colt, see it grow up, put up with its tantrums though the hormonal years. I'm fine finding someone more like myself. A little beat up, a tiny bit run down, but still has some play time left in 'em.
Not sure about the rest of you but at age 42, my bones already creek a little bit.
The only thing evil needs to thrive, is for good men to do nothing. - Edmond Burke