As a child, I would go with my Dad on his sales trips. At that time, my dad sold Hoover vacuum cleaners. On his trips to the retails stores he would stop and train the owners about the benefits and uses of his product line.
At a time before we had cable TV, mobile phones, Walmart, or the Internet, if you had a problem you would go down to the local store and look for a new product that would solve that problem. The owner was the expert, so you would tell him of your problem and he would recommend a solution. These were simpler times, with fewer products in the market.