He had previously been a professor at a medical school and was a very good teacher. In the three years I was there, I learned a lot of sleep medicine. You can't treat sleep apnea without compliance. Some doctors consider a patient being in compliance if the patient uses CPAP three hours a night, three nights a week. They might be considered to be compliant, by that standard, but their OSA is not being treated effectively at those levels.
Compliance is a result of comfort and effectiveness.
You can have the most effective CPAP machine, but if the interface is not comfortable you are not going to use your CPAP machine. My job has always been to provide a comfortable interface and to provide a CPAP system that is effective. While at the sleep lab I followed over 500 patients on a regular basis. In the beginning I called them 24 hours after initial setup to find out if they were having any problem. I called them again in 48 hours, then at the end of a week, then at the end of the first month, at the end of the second month, and at the end of the third month.