That is a lot harder to say after the age of 35 or 40. My social circle includes many alternative people in organic farming where I have occasionally pitched in to help, and I have also volunteered with WWOOF for food and accommodation when traveling. This kind of work, even if a mere couple of hours a day, really, really starts to suck after your knees and back begin to age. And it is not that I have given up and settled into a sedentary lifestyle – nowadays my travels are bikepacking/bicycle-touring where I do 100 km+ day after day, but that exercise is a lot easier on one’s body than the repetitive motions of farming.