FWIW?you lose all depth perception with monos. Back when we had the AN/PVS 7Bs, I would keep mine tucked away until we were sitting still at a patrol base, in an OP, or on an ambush site. Also, keep in mind that once you use them, it's going to be a good 30 minutes or more before you can see anything without them. (Your eyes need to readjust.) It will take even longer is you smoke, dip, or drink caffeine.