Every day, every situation is different in the world I work. I try to be prepared, as much as possible, and this includes owning reliable equipment.
Although having a backup for each piece of gear is a great solution, it's not always realistic to have it attached to my belt.
When running onto basketball court for post game interviews, I'm not pushing a cart with supplies around the court, nor do I have an assistant to shine my shoes. Yes, I might have a pelican packed with backup equipment on site, but realistically, there isn't always a second take or another opportunity to switch out gear.
What leaves me baffled is that Sound Devices Tech Support assumed it was a hardware issue. It was explained that the day prior, the machine completely froze. The following day, none of the inputs would activate. SD offered to send me a loaner, for $80/day. This, along with the initial card and firmware issues, have left me with a different opinion about how this company operates.