I am doing the P90X 3 program, which requires you to go from one exercise to the next without rest. Changing the resistance bands quickly and moving them from place to place is a bit of a hassle. For example, I will use them for a pull up alternative with the door mount, but then I will use them for curls for other shoulder exercises which require a lighter load. So I have to pull the bands all the out of the door mount, remove a couple of bands, do the exercise, put the bands back on and re-thread it through the door mount. Because of the alternating nature of the program, this gets annoying really fast.