I am generally not the best at sticking with workout routines. The fact that I made it through P90X was nothing short of a miracle. But I've been using this book every night for a week and I'm really loving it. Most of the routines can be done without any equipment and they're just the right amount of intensity. There's some burn and a little soreness the next day, but it's not so brutal that you can't lift your arms. I like the pacing and the visual index makes it easy to jump to any routine.