Two reasons 1. I did not feel it gave me better sleep as I was still feeling fatigued as if suffering chronic fatigue syndrome and 2. I was to go on an overseas 2 week holiday so did not want the bother of CPAP gear.
So I abandoned CPAP for 2 years.
But then an angina incident sent me back to the heart specialist who doubled my heart medications and instructed me to resume CPAP at night as he assured me it was significantly helpful.
So back to CPAP again with my old nasal mask. But this mask was showing its age so I purchased a Resmed Airfit F30i full face unit. Assuming I was big headed I ordered the large sized mask with medium nose fit.
2 days of frustration followed with air leaks keeping me awake until I finally woke up to the fact I should have ordered a medium size. But the solution was simple, putting a rolled up sock at the top of my head raised the F30 so it fitted properly without noisy leaks.
The result last night - an AHI reading of 0.6 with no air leaks registered.
And of course, I'm now FINALLY getting a good night of sleep.
So what was going on before with the nasal mask?
I suspect it was because during the night I started avoiding CPAP and breathing through my mouth meaning CPAP was NOT preventing sleep apnea. Previous attempts at devices to keep my mouth shut did not work for me and after abandoning CPAP I did attempt using a special mouth guard to stop snoring. But the fatigue persisted so that obviously did not work either.
So folks, I'm posting this to help any of you who, like me previously, have not found CPOP gear helpful. You might need a full face mask instead of a nasal unit.
It has been a long road for me, now 85. My first attempt at using CPAP left me frustrated as I just could not get used to having a contraption on my face so I gave up. A second visit to hospital for a sleep study convinced me I had to try again and did eventually get accustomed to CPAP, although, as noted above, no miraculous changes to my health occurred. So I used CPAP for several years before giving up.
And it surprised me that going back to using CPAP was a no brainer as far as tolerating it was concerned. I had no trouble using it again.
So there you go folks, light at the end of the tunnel
BUT, avoid being an idiot yourself and 
