No matter what kind of horses you have or what you do with them, one thing is universal: they need their hooves trimmed regularly and in many cases they need shoes.
While in the past the local blacksmith shod horses when he wasn’t busy making iron pots, tools, nails, and the like, today’s farrier is a specialist and an expert in equine hoof care. He or she has studied equine anatomy, biomechanics, lameness, and hoof health, and knows how to adapt the work to the varied needs of different types of horses. Chances are they are a self-employed professional who also has to juggle the business end of things including appointments, finances and accounting, buying supplies, getting the truck repaired, and so on.
Typically, a young man used to apprentice for years under an experienced farrier, gradually learning the profession and eventually taking over when the older man retired. Today, the future farrier goes to a specialized school, becomes certified, and probably works for a couple of years for an experienced farrier before striking out on his or her own.