I take it very seriously. What I did: I bought an external hard drive, a cloud with two-factor authentication, and I regularly review archives of old projects to see if they can be deleted, compressed, or archived. That's why it's useful to have a manager that allows you to work with archives: for example, https://commander-one.com/extract-tar-files/ describes how Commander One helps you open TAR archives on Mac and search for files in them without unpacking them completely. For me, this is a way to keep things tidy and avoid having a bunch of "forgotten" files that just take up space and may be vulnerable. I regularly "clean up" — and that gives me peace of mind.