The most important skill of a trimmer is to observe the horse during movement and interpret the pattern of hoof wear.
Early on, before I knew anything about the natural asymmetry, I observed that both my horses showed more wear on their lateral sides. The white line always seemed more separated on the lateral than the medial side.
This is pretty easy to explain now, as the lateral side receives more pressure during movement it also receives more wear, especially at the toe, as the hoof rolls over that lateral toe more than the medial when leaving the ground.
In the beginning I misinterpreted the fact that the white line separation was wider and deeper laterally and lowered the lateral wall. This was a mistake, that I luckily caught in time, before the hoof looked like these:
The hooves in the picture above also shoes a wider lateral side than medial, but this has nothing to do with "natural asymmetry" as now the lateral walls drift away and the coronary band is no longer straight but curves down medial-laterally. This asymmetries has to be distinguished from the natural asymmetry.
In summary, the principles of natural asymmetry of the hoof and the patterns of locomotion as detailed in the previous entries of this blog requires hoof care practitioners to balance the surplus of wear on the lateral side by adjusting the medial side if necessary.