It's been 7 years for me. I have severe obstructive sleep apnea. The sleep lab decided to cancel the sleep study after a bit over an hour, and titrate me right away, because they were afraid I was going to have a stroke in their sleep lab.
I started out with a nasal gel seal mask that took me several months to fully get used to. I would adjust them incorrectly, then end up breaking the support tab that presses against the forhead. I finally learned that the secret to adjusting the mask is to not overtighten it. The initial tendency when it leaks is to believe that you need to strap it down tighter. In reality, this just causes it to deform your face more and create more air leaks. It also means that as you roll over on your pillow, and your face changes shape slightly, that new air leaks will be created. The secret is a light pressure so the mask basically floats on your face.
I did try nasal pillows for a while and could tolerate them, but went back to the mask. Eventually, I switched to the Nasal Aire II system, which is a nasal prong system. Basically, instead of nasal pillows, which press against the nostrils, a nasal prong system actually inserts about a quarter inch into your nostrils. It looks like a large oxygen supply you see heart patients wear on TV. I love the thing!! I can sleep on my stomach, wear glasses to read while wearing it, few leaks and no adjustment problems!
I'm going in a couple weeks to be retitrated again. My new sleep doctor wants me to try the new Swift mask, which is a nasal pillow system. I agreed we would start out with it, but if I don't like it, we'll switch back to my Nasal Aire II and titrate me with that instead.
Everyone seems to feel the Swift is the hot new mask. I'll decide for myself in a few weeks.