Who or what determines the useful life of a CPAP machine? Does the machine need to fail or not work properly to justify requesting a replacement?

My CPAP supplier sent me the wrong mask size and style, twice. They didn’t want me to return the 10 or so masks. Any suggestions on non-profits in the U.S. who will accept such donations?

I haven't kept up on the latest technology in regard to CPAP machines. Currently I have the ResMed AirCurve 10 ASV. Is there a newer machine that is incrementally better than what I have now, in terms of effective therapy and/or reporting? Thank you.

Hypertension and tinnitus are just two conditions connected to sleep apnea. I’m curious to know if sleep apnea could be a secondary condition to one or both of these two conditions. If so, where can I find the citations? Thank you.