When they put me in the ground. No one in my family (well, the males - I'm the only female that's ever actually had a career, such as it is ;) ) has ever retired. My mother and grandmother had to finish up my 85 year old grandfather's last order when he died (he sold specialty advertising) and when another grandfather "retired" and sold his snack food company he bought a functioning 1500 acre cattle ranch. He had an office and went every day. I'm not sure he did much more than drink and smoke cigars but he always wore a suit (I never saw any of my grandfathers dressed down in less than a dress shirt and tie) though considering himself now a cowboy, he traded in his tie and wore a bolo
My Dad is 72 and still working though mostly part time as they travel a lot.