A horse, in its natural environemt, travels an average of 15-30 km (10-20 miles) per day with its herd, over various terrain. The hooves adjust to the type of terrain (whether desert sand, prairie sod, the shaly, rocky ground of Iceland, or the wetlands of the Camargue): horn growth and wear are in balance, and the functionally optimal conformation and shape of the hoof is naturally maintained. The hoof remains supple and elastic through daily contact with mud or water as the horse drinks. It does not have, nor need, any type of grease or oil or artificial moistening agents.
Under the care of humans, however, horses almost always fall short of their natural (and biologically required!) amount of movement. As a result of this, in order to imitate the natural amount of wear on the hoof, it is necessary to trim it--far more often than every 6-8 weeks. For hoofcare specialists and horse owners working according to Dr. Strasser's methods, trimming in two week intervals is normal, if they are not riding enough. This makes it possible to keep the sound hoof in its physiologically ideal shape (by, for example, preventing the bars from growing too long, and the heels from growing beyond the level of the frog and bulb of the heels, thus doing damage to the interior of the hoof, especially the navicular region). It also allows the healing of deformed hooves and other hoof-related ailments (contracted heel, laminitis, navicular syndrome, thrush, arthritis, to name a few). However, a certain amount of knowledge about the function of the hoof and its physiologically proper shape is necessary for this endeavor.