I remember being 30, but I don't remember much.
I've found stretching
after riding helps me maintain range of motion, general flexibility, and reduces cramping. So I try to stretch at least a few times a week, and certainly after a longer (more than a couple hours) ride. I'll try to stretch hamstrings, quads, and calves every 50 miles or so on ridiculously long rides, while stopped for a "nature break," food, or water.
I've read it's easier to pull a muscle stretched cold, so I don't do that unless it's cramping.