Do You Keep Backup Parts?

I have found its a good idea to keep spare parts. In the first 6 months i have experienced a broken hose which could be temporarily fixed with gorilla tape. But a mask break is harder to fix and I had my Resmed Mirage Libery break on me after just 2 weeks of use and it refuses to be repaired
I do not have a backup machine yet but i can get a loaner from the DME within a day if i need to. One of the advantages of working with a DME

I keep my old hoses and masks. Why not?