Sore feet will sure slow you down. You need to take good care of them.
Before I started using this stuff I had cracked heels which were often very painful and would bleed. After a couple of weeks’ use I had heels (feet) like a baby’s. I use it every day now and have never had any problems with my feet again – including blisters.
Hill-siding (and ill-fitting shoes) are the worst cause of blisters. Liner socks help enormously if you are going over a lot of very steep country. Blister pads should be applied the instant you feel a ‘hot spot’ starting up.