I used to save everything by default and over the years (~20) my storage requirements started getting out of hand.
So I had a change in philosophy where I decided to throw everything into a "to delete" folder and start with a single flat folder structure and go through everything file by file and put it in the "keep folder" and really evaluate whether I needed it. As a result I ended up with about a 90% reduction and I don't feel like I'm missing anything.
Yeah, this. The data I am most concerned about is not even 1GB after compression. That's all my $HOME configs and all my projects I am working on. Then I have some open datasets I like to fiddle with (mostly *.sql.zst compressed DB dumps) which I periodically dump on my Linux server (weekly with rsync) and finally -- video.
Video is obviously like 99.99% of everything but I have made sure to store all the sources of it (mostly downloaded playlists from YouTube) and I have scripts that synchronize the videos from the net to my local folders. Even tested that a few times and it worked pretty well.
So indeed, in the end, just find what's most valuable and archive that properly. In my case I have one copy in my server and 5+ copies on various cloud storage free tiers. All encrypted and compressed. Tested that setup several times as well, I have a one-line script to restore my dev $HOME, and it works beautifully.
So I had a change in philosophy where I decided to throw everything into a "to delete" folder and start with a single flat folder structure and go through everything file by file and put it in the "keep folder" and really evaluate whether I needed it. As a result I ended up with about a 90% reduction and I don't feel like I'm missing anything.