Do you have a horse with a hoof deformity? Draumur, my 14 year old Icelandic gelding sustained an injury as a yearling involving the coronary band on his left hind foot. As a result his left hind hoof grows out with a deep groove from coronary to the ground with thickened hoof wall growth on both sides. When I got him as an 11 year old I was told to keep him shod to keep him sound, although he never had any lameness issues.
An old injury to the coronary band causes a deep groove in the hoof wall.
After pulling his shoes, transitioning him to barefoot was a bit of a challenge: his heels were underrun, wouldn't grow, and his toes grew long. Draumur runs at the very low end of the size spectrum, so the choices were limited. When I measured him for boots I found the best fit was with Easyboot Trails in the front and Easyboot Gloves with power straps in the back. This combination has proved to be a success. The boots stay on in all gaits and he tolts reasonably well with boots on all four feet (weight/material on feet always being a concern with gaited horses).
Easyboot Trails for the front...
...and Easyboot Gloves for the hind.
Here we are ponying a young mare.