When I was in my thirties, exercise was nice but not as necessary. With work and kids, exercise simply took lower priorities. After turning 40, my hair started to turn gray, I really felt my age but dying my hair is still a quick fix ;). Recently, when I wake up with a stiff back, notice body hair turning gray (how do you dye that?), have chest pain after a long and stressful day, exercise suddenly becomes the necessity! I now know why some of my colleagues in the forties and fifties exercise so much more regularly, because this enables them to work better on a daily basis.
I previously mentioned the very intensive and painful iPhone exercise program 7-min-work-out and how Yoga Studio was better. Recently this program has an upgrade called Sworkit, and I am switching from Yoga back to Sworkit. Instead of just having 14 30-sec exercises, the new program allows users to select many different exercise, each lasting only 30 second. I made a custom collection of ~180 different exercise, some building strength, some aiming at flexibility or relaxation, some on neck, arm, leg, back, etc. Then every day, I just specify the length of my work out (e.g. 20-30 min), the program will randomly sample exercises from the collection, so every day I get a different yet comprehensive workout. In the beginning, my body sores after an exercise, but now every morning after the workout I feel so GREAT! This exercise is extremely efficient and very easy to do during travel (some exercises on the floor and some on the bed, so no need to bring yoga mat).
I wish I had taken better care of my health when I was younger, but it is not too late to start now.