I'm a windows user so I put files I want to store long term on onedrive. If it's a really important file (old photos), I have an external hard drive for backups as well.

Code is all backed up on github

Files that I don't care about losing someday remain local on my PC and those get messy. Most things end up in my downloads folder and I delete them every couple months.

Every couple years I'll get a new laptop and my strategy is to move over nothing. No settings, no files, no wallpapers. Just start over from scratch