By definition, the data you DON'T back up regularly is data you DON'T care about. Since most (all?) PCs have a spinning disk in them which has a finite lifespan, a good backup is critical. And with Terabytes of storage available for cheap, there's no excuse for not backing up. Unless you don't care (which is entirely possible)...
So, how many have made a backup of their machine for this month?
For myself: Two PCs down and a laptop down, two phones to go. Phones? Yep, you're smartphone is just a little PC with a phone app...