My dad was forced to quit at 73 by health. Last year he turned no laps for the first time since the 60s. This year he is still AFU but we rented the pavement track and he did multiple short sessions, probably 40-50 total laps. I snuck in five, first time on pavement, ready to push the car, not ready to wreck it since it's not mine, quit while ahead.
If you're ever around the Mid-Atlantic area we need to figure out how to at least get you some hot laps in one of our sprints. Full size, 305 motors, cheaper than mini sprints by far. And we have had many old racers in their 70s with us, oldest active now is 73.