What makes it worse, I like to save every frame. I rarely discard the bad ones. I know that makes no sense, I must be OCD.
About once or twice a year I pick up a new Seagate or Western Digital portable HD while I'm shopping at Costco, usually one or two TBs. The solid states are more reliable, but they're more expensive. The traditional HDs don't cost as much. I carry a small SSD HD in my camera bag, and the other HDs stay with my laptop.
I download all the best pics to individual folders after every shoot. Then, when it comes time to clear a card, I back up the whole thing to a separate folder and date it. Some files get backed up twice.
I know this is a terrible system, but it works for me. I'm too ADHD to do a proper file system.