I wanted to take a minute to explain why it is important for your farrier to top-dress your horse's hooves. I know not everyone knows what that means, so I'm going to try to explain it.
Some horses have hooves that tend to "flare" out, due to their conformation. This means that instead of growing straight down, they grow kind of sideways/out. You might call them "dished out" or "pancaked." Flares can also be caused by overgrown hooves, laminitis, etc.
Oftentimes the laminae becomes stretched from this, and can cause other problems. Top-dress can also treat/prevent cracks.
Many horses only flare a little, so it is easy to maintain and sometimes can be done only every other trim.
Here is a side-by-side photo demonstrating what I'm talking about:
This is before Justin had finished the trim on this horse. This mare had laminitis but made a truly miraculous recovery. Justin had to remove an extreme amount of flare from each front hoof and also had to trim back the "toe." (Foundered horses tend to grow a lot of toe which needs to be removed or their condition will worsen. I.E. Bone will puncture through hoof)
Here is the finished hoof: