I continuous backup important files/configurations to my NAS. That's about it.
IMO people who redundant/backup their media are insane... It's such an incredible waste of space. Having a robust media library is nice, but there's no reason you can't just start over if you have data corruption or something. I have TB and TB of media that I can redownload in a weekend if something happens (if I even want). No reason to waste backup space, IMO.
Windows will eat the bootloader every time it updates the boot partition. Which generally isn't a whole lot of the time, but it's always a surprise, that's for sure.