If you're planning a big project for "when you get the time", DON'T.
I thought the deterioration of strength, flexibility, coordination, etc. would be something like linear: after 50, lose 1% every year.
It's not.
There's a cliff just ahead of you, and you're going to fade away sharply sometime before 70.
I can't see, even up close, can't pick up an aspirin without flipping it across the room, can't carry a jack stand more than 50 feet. No, there's nothing wrong with me, just born 1945.

Do it while you still can.