How does one know when to retire?

How does one know when to retire?

I loved teaching in case classrooms with 40–70 or more bright people debating important issues. Just loved it. I was in flow in there. After 36 years doing that, I realized one summer that I was really tired and not looking forward to going back, starting over with new people, committee meetings, more stacks of exams. So I stayed one more year just to be sure. And yup, it was time to stop.

I met a man on an airplane who’d gone to one of our programs. I asked whom he had for faculty. He said he didn’t remember his name but he was really old. I didn’t want to be that guy. So right time. At my exit interview, my associate dean asked what I was going to do. I had a list of 12 things. He said I was better prepared than anyone else he’d talked with. Many of my colleagues seem to have nothing else to do.

Since retiring, I’ve written two (more) books, built a website, taken up painting, continued teaching taekwondo, played in multiple annual modern, hickory, and gutty golf tournaments, taken up pickleball, organized 30 years of photo albums, and gotten two new grandchildren. I remember my global travels fondly, but grew weary of any travel. All over consulting, Africa, Europe, South Central and North America, Asia, India, Australia. 

Now, I take naps when I want. Every day is Saturday. Trying to wring fullness out of every minute n go into that dark night in a four wheel sideways drift, grinning and shouting wahoo!

What's your purpose in life?  When and how will you know when to slow down and step back?  Or will they remember that you were old, but not your name or what you did?