My dad is in his seventies, and just built an addition on the house alone, by hand in his free time while working a full-time job. From pouring the slab, to framing, to roofing, to electrical just because he was bored.
I think there's a lot to be said for arriving at your seventies still being the kind of person who goes, 'I'm bored, I need to go and build something with my hands.' There's obviously a lot of luck involved in not having any major health complications, but fortune favors the prepared.
Being relentlessly active and curious is a really, really big deal as you age and it's so easy to fall in the trap of retiring, and sitting on the couch with a beer watching Fox news.
There is a concept of healthspan, and elderly in their 70s who just have weak muscles & less energy with no mental or other physical health conditions or medication requirements.
Personally, dying at 70 seems about ideal to me. Of course maybe I'll change my mind if/once I reach 70.