A big running dog will wear out a pair of boots in one day; if they aren't lost in the first run.
The key word is conditioning. My dogs don't have problems because they run on ruff ground daily.
HOWEVER the best thing out there for foot conditioning is:
TINCTURE of BENZOIN used by athletes word wide. Call it up on line.
The motorcycle inner tube also works. On any type of boot you must use caution, because of chaffing on the legs. Use vet wrap around the legs to protect against boot chaffing. Boots are really a pain. Remember a dogs front feet are different than it's rear feet. A set of four boots just don't fit front and rear. There is one company making front and rear boots but they only last a few hours in ruff terrain.
