I'm also for an easy spin or easy walk. But sometimes, I need 2 rest days a week now. Not usually consecutive, and sometimes one will have some very light exercise. The boot camp stuff stresses me in a way that riding doesn't. While it's good for my bones, it's not so good for my autoimmune system. I will be more apt to skip a day there than skip riding, although I have missed very few classes in the past year since I started. Rest is part of a total program, and very important as we age.
I'm 58, at least for 5 more weeks.