Anything I can download again doesn't get backup, but it sits on a RAID-1. I am ok at losing it due to carelessness but not due to a broken disk. I try to be carefully when messing with it and that's enough, I can always download again.
Anything like photos notes personal files and such gets backedup via restic to a disk mounted to the other side of the house. Offsite backup i am thinking about it, but not really got to it yet. Been lucky all this time.
From 10tb of stuff, the totality of my backupped stuff amount to 700gb. Since 90% of are photos, the backup size is about 700gb too. The actually part of that 700gb that changes (text files, documents..) amount to negligible. The photos never change, at most grow a bit over time.