I used to only use them on the front legs because my gelding had a previous suspensory injury from a few years ago that I was trying to avoid re-injuring.... then I got a hind suspsensory injury and bought backs... and then I bought the hocks... so now I will use all three pairs before a run!
Mine have never been to the barn yet. I use them on myself at night to prevent leg cramps. They really work! I am going to order another set for my mare.