When you normally replace your CPAP, I suggest you hold on to your old one (not the recalled ones, obviously).
I kept the one from 2005 when I replaced it in 2009. My 2009 machine broke in 2016, and I was fortunate enough to find that the machine from 2005 was still in working order, and that there were a few filters stored with it. I was able to use it until I got a new DreamStation1. When the DS1 was recalled, I was able to find the machine from 2005, and use it until a DS2 showed up at my house unannounced.
Should the DS2 break, be stolen, or be recalled (this possibility was suggested by the LankyLefty), I can still use the machine from 2005 (a Fisher & Paykel HC-231).
Note that you want to keep a recalled machine to support a possible lawsuit in case you get ill (or already are), but do not keep it for use!