How often a horse needs trimming depends on many factors, particularly how fast his hooves grow. A shod horse usually needs trimming every four to ten weeks (depending on his growth rate), since there is no way for the hoof to wear naturally. (Feet tend to grow faster in summer and slower in winter, but there will be a more consistent difference between individuals than between seasons.)

If the horse is barefoot, trimming intervals may depend almost entirely on how fast his feet wear. If he has ideal conditions for space and exercise, he should wear the hooves at about the same rate they grow; they seldom need trimming. The feet may occasionally need to be smoothed to prevent or halt chipping or cracking, but very little hoof wall needs to be removed.

By contrast, a horse in a stall, pen, or soft pasture will need regular foot trimming. If the foot does not have ideal conditions, it may need trimming even more often than if the horse were wearing shoes–to keep the foot from splitting or cracking in dry conditions or splaying out in wet conditions. In poor environments, shoes can protect the foot that would otherwise break or crack. Diligent and frequent trimming and smoothing may be necessary.

Similarly, a horse with a foot problem (severe crack, chronic founder, crooked legs and feet that become unbalanced because of uneven wear, etc.) needs to be trimmed often. With an unbalanced foot or a chronic problem in which part of the horn grows faster, frequent trimming to remove the regrown horn can keep the foot at its most ideal shape and balance. Trimming can also relieve pressure on a crack and help it grow out faster. A severely cracked foot may continue to crack if a hoof is allowed to grow much between trimming intervals; the long foot puts more widening forces on the crack