, This is a good question. I don't often check my numbers, but always do if I've had a bad night of sleep or haven't been feeling well.
It's easy, I use the ResMed AirSense 10, which comes with the myAir usage tracker program you get for free. I can quickly check events/hours slept directly on my machine, or I can visit the myAir tracker online and find out how long I slept with my mask on, my mask leak numbers, how many times I took my mask off during the night, and the number of apneas I averaged. I can also review my usage "scores" over periods of time to see how I'm progressing.
Best, Tamara, SleepApnea.Sleep-Disorders.net community advocate