The newer and higher end models are self adjusting. They sense what you need and adjust the pressure in real time. Both of the current machines I have do this (one for home and one for travel, even though they are basically the same).

That said, I still have to get into the technician adjustment side and make some modifications (the average person is not supposed to be able to get to these adjustments but a quick search in the internet will give the button key sequence to get into that part of the program). I have to set my maximum pressure or I will wake up sometimes in the middle of the night with the machine screaming and my gut "pumped up" with air. Uncomfortable.

Since I have lost close to 100 pounds from my heaviest I can now sleep on my side without the CPAP. But on my back I still need it and can't sleep on my stomach like my wife can. So if I have to do without the CPAP I can manage but not very well. Sleeping on my side my shoulders get sore and I have to turn over after about 30 minutes to a couple hours. This wakes me up so I get lousy sleep but at least I can sleep some. When I was heavier even sleeping on my side was difficult. People don't think about it but when a person is fat they will likely also have a fat tongue that blocks part of the airway.