Had a elevator business for 10 years. Extremely cut throat industry. Some years made money some years not. My advice, you better be a person who loves working more than anything else in the world. not just working on elevators, go home or office and work some more after your workday.
The day after my first daughter was born I sold my company to a competitor. No way I wasn't going to be around for her and her mom.
I'm proud I did it and I walked away with some money in my pocket but have known some extremely sharp elevator people to lose it all for the sake of there ego.