FWIW, my podiatrist made me a new set of orthotics. I wore them at the gym and figured I needed to break them in. So I kept wearing them over the next couple of weeks and I kept getting blisters on the soles of my feet. I only discovered them when I actually looked at my feet because I don't feel them happening. At first I was stumped and I didn't put 2 and 2 together. I finally went back to the podiatrist and he had them put a different cover material on them initially and that was causing the problem. Who would have thought!!