here's one thought: I know as a sleep technologist that not all new patients understand that their machines have a humidifier function, or that it needs to be turned on. Unfortunately, some of the people who set up new patients with CPAP don't spend the time necessary to show them how to adjust these settings. Or, they simply forget to turn it on and the patient, not knowing it's available to them, doesn't know any better.
If you live in a dry climate, the humidifier is a necessary feature. When in AZ, I would fill up my chamber and go through the whole chamber in one night. Here in WA state, I fill to the lowest mark and have water leftover.
Some people don't like using it but they also live where there's more humidity in the air, so it's less useful. And some don't like it because they may actually have it set too high, and they get something known as "rainout," or condensation in the tubing that eventually collects in the mask.
If you're unsure about your humidifier feature, you may want to check your settings to ensure it's on and at a level that can provide you with more moisture comfort. If you're not going through any water at all and the machine is set to use humidity, it could also be a mechanical error that needs fixing.
Hope this helps you or someone else! Best wishes, Tamara (community advocate)