Kind of tangential, but I've seen some folks struggle with doing "60 to 0" (the opposite of 0-60 acceleration) in retirement. One uncle of mine, for example, had been hustling at various odd jobs his whole life and thought he'd just stop. Well, after a few weeks of sitting at home at age 65 in front of daytime TV doing 12 ounce arm curls, he felt he was going to lose his mind. He took a job as a 24-hour on-call locksmith. Other relatives and acquaintances, though, found enough to keep them mentally engaged in retirement, even if some of it was work-- in volunteer jobs.