I am 45. My vote would also be not to leave it too late. The problem is finding the time of course. It would be nice if employers, including the employers of the self-employed, were a little more flexible. I think if people could take 6 months to a year off in their 40s for something like a thru-hike it would pay great dividends in the long run. That's another thing I have against mandatory retirement at 65. People should spread the work out more. Sure you should slow down some after 65 to take time for more things, but it seems nuts to go from long hours with little vacation to zero hours overnight. It seems we live in a world of kitchens designed by men, and lives designed by corporations.