Years back before trade schools existed you needed to have an advisor to learn a trade. In those days, everything came through experience and first hand knowledge, there weren’t Youtube videos, or even plenty of books, on how to learn trades like smithing or carpentry. Since the advent of trade schools, the advisor method of learning a trade has gone by the wayside, regulated out of existence or damn close to it. Those in charge say you need standardized tests to test someone’s level of skill, which is patently ridiculous. We were lucky enough to have an advisor who taught us the basics of Heating & A/C work when we were still in middle school. Our dad’s friend was called Harry, and he did mobile heating repairs out of his van. Harry had learned everything on his own, and knew so much about air ducts and furnaces. He entirely made his own sheet metal in his workshed, so that he’d craft his own custom air ducts. Harry did not teach us about cooling units, that was “after his time” he always said. But, he taught us the basics of heating repair, and the skills we needed to make our own air duct. After high school, we went to school to become certified officially, and that is where we started learning about a/c units. We were already experts in furnaces and ventilation systems. But, we had a lot to learn about AC. Our advisor taught us a lot, although we got the rest of the way through strenuous work.