Is there such a thing as a "sole protector" for shoes? A lot of the time on ballet flats, the sole is so thin that it wears out way before any of the rest of the shoe. I was wondering if there was something you could apply to the sole of the shoe when it's new that would help minimize the wearing out of the sole, and thereby put off having to take them to a shoe doctor and have them repaired or resoled.

Thanks!