An ex-client of mine has a brother has his own plumbing business. Since I am a real estate agent, it is always good for me to know handyman like him so I can recommend to my clients if they have plumbing problems.
My ex-client introduced me to him one time and his brother sure knows all about plumbing. He dressed very smart but casual, unlike any plumbers I've seen. He started off telling me why and how he started his business. Then on it went. I suspect he probably took Sales Training Courses in plumbing. I was very impressed with him and definitely will refer him to my clients in future.