Also, would it really hurt to travel some time without any boots at all? This is a good idea, but do it BEFORE SHTF.    It'll toughen up your feet, which is never a bad thing. However, you may get bits of glass, wood, etc in your feet if barefoot, even if you're walking on roads or sidewalks. Post-SHTF you probably shouldn't do it except as a last resort, but pre-SHTF it can be useful conditioning.