I had a friend in the car wash business. What I remember was the less people you had, the more money you would make, and the less hassles you would have.
Said when buying a car wash, do not accept the car count the owner gives you. You need to sit yourself in a good vantage point and count the number of cars going through yourself. If you hire someone else to do the counting, the owner will spot him, and bribe him to report a higher number.
It is a mostly cash business, so trust is necessary unless you handle the cash register yourself.
There are industry associations that hold conventions where you can see all the latest equipment and attend seminars to learn how to maximize profits.
Lots of mechanical and electrical issues. Chemicals are getting better all the time.
Most important person is the one that focuses on upcharging the customers to buy additional services such as tire gloss, spray wax, hand wax and full detailing. They also do headlight polishing and windshield replacements.
First car wash is often a huge learning experience. Lots of Mr. Soapy wash franchises going in around SoCal.
