Well, that was my thought when I changed careers, because I can do this as long as I can talk and write. Several people just retired from my clinic and they are in their late 70s. However, in order for me to keep working, I have to take 30 CEUs every 2 years, so that is a cost and time to maintain my license. I guess it's not a huge deal and it would be easy to go down to one or two days where I work.
My dad worked until he was 85 or so and my mom's dad worked until the day he died, from the after effects of a car accident, when he was 91. He made most of his $ after the age of 65, and his colleagues were continually bugging him to give up his customers to them (he was a scrap metal dealer). But, in my head, there's a lot of stuff I want to do, yet when I have the time to do things, I seem to get stuck in my patterns of doing whatever I do now! I think part of it, is that I have spent a lot of time making my career such a huge part of my life and insisting I could never be a stay at home mom (which is true), that I get truly antsy unless i am busy and have plans all of the time.