My dad is 80 and retired from his career (advertising) but goes to work 3 days a week. He has been a bank courier for a few years now. He’s always been a worker bee.
He lives by himself, cooks for himself and enjoys most of his life. He has had some, but very few health problems and he’s not especially “fit”. I can easily see him doing this for a few more years.
I hope it’s hereditary. :-)
I’m past the demographic: June 19, 1929.