Just replaced S9

Totally depends. Your comfort level, level of apnea (severe vs. mild), how quickly (or if) you can get a backup from your DME. Do you have a copy of your prescription at an online retailer?

My DME will only provide a free backup while you are still in the rental phase. After that, you have to pay a rental fee and that isn't covered by insurance or Medicare. YMMV.

I'm still looking for a good price for a backup for either an S9 or Airsense because I was one of those rare folks who don't respond well to Respironics' algorithm. Actually, I did have one, but it was damaged in shipping, so the seller kindly took it back. It's pretty easy to get a good price on the 560 autos now with the new Dream out.

You have to look at your unit as medication. Can you go a week or two without your metformin or blood pressure meds? Some CAN, but for a lot of us, our health deteriorates after a day or so. I got the headaches back.