I'm closer to 80 than 70, but I'm still working because when I retire I trade a $193k salary for a $13k pension. It doesn't seem like a good financial trade off just to be able to sit around the house.
Especially if you don't feel like sitting around the house. Many of my friends in their 70s put in nearly a full time job of volunteering at church or other organizations, although I guess it's easier to take a vacation from that than from an employee position.
That’s the way I’m looking at it and I just turned 60.
It’s not like my job as a Professional Engineer is going to kill me. Besides that, my wife is 43 and if I retire she’ll just have that much more work for me to do each day.
If your work is you passion then you are in the right place. I have been retired for 7 years (high tech Silicon Valley). Not one day have I wondered, "How are they doing?". Life is good. I'm busy, in shape and travelling. Love it.