When are you too old to live?
Granted, sometimes restrictions are placed on certain occupations that involve the safety of other people and age is used as a factor but how old is old, really. I live in a community that is heavily populated with retired people. I am in my late 50s but there are people in their 80s that I cannot keep up with mentally or physically and sometimes both.
Another thing is that I find it better sometimes to acknowledge a limitation and accept it when it does occure no matter what the reason. An ounce of satisfaction is worth a pound of doing. My yardstick is "Do I feel good doing it?"