Of course you're free to go about it how ever you want, but that's not business savvy in any way. How often do you think you should clay a car? If you think you have such a huge market available to you that it's ok to only see customers once or twice a year, with them paying someone else to maintain their car in between, then good on you. Is it good for business? Not at all. Even if you can convince them that you need to clay their car every month, you're basically lying to them and they may eventually figure that out and not return.
I haven't gone full time with my own business yet, but when I worked under my friend with his business, we had many repeat customers, some every two weeks. They didn't want to touch their car. They wanted to pay us to completely maintain the condition of their vehicle. One particular guy had a new Jag XKR and 7 series BMW. He also got us a lot of business from his neighbors. We're not going to run a clay bar all over a brand new XKR every two weeks.
Then throw in referrals to people who don't need or want to pay for that extensive of a detail, and you refuse to work a on a car for a referred customer? How is that going to look to the customer that referred you? Probably not going to refer you again.
You can say it's half-assed, but it's expanding a customer base. I would easily tell you that vacuuming and not using an extractor on the carpet and floor mats is half-assed. My buddy's mobile detailing business was consistently bringing in over $10-$13k a month in revenue with only one truck and two guys working. Some of the best profits came from "wash and wax" customers with weekly scheduled visits to businesses where we could do 6-10 cars at the same location before lunch.
