The "turns down 4 out of 10 jobs on purpose" part is doing a lot of work here and it might not mean what people think. I know a couple shop guys and what they actually do is quote high on the jobs they don't want, or say they're booked out three weeks, and the customer walks away on their own. That's not the same as telling someone no to their face. Sometimes it's also a parts thing, like they can't get the part so they just pass. So yeah, it's still turning down work, but "on purpose" makes it sound like some kind of brave choice when a lot of it is just pricing yourself out and calling it selective.