We are using them in outdoor Marine environment. no break in period needed. I really like them, they are exactly what I was looking for. el empaque venia abierto y roto, pésimo. Cuando se apaga, hace un ruido y eso a mi no me encanta, porque a veces se apaga sola y me asusta jajaja. You have to wear them for a few days before you can see the benefit. My first choice was a Nike sandal, but the upper arc was too small for my wide feet. All I can say is wow. Just moved into a new house, with new garage. Disappointed to the utmost.