Similar advice if you make electronic music: always save lossless raw audio (wav, flac etc), not just project files. Software updates break project files, hardware updates break old software, backwards compatibility is often imperfect, licenses expire, old VST plugins become unusable, source files for the project become lost, etc. It's always safer to have a pure raw audio export of all your projects even if they're unfinished because there's a chance you'll want to use or reference those unfinished snippets in the future.
Oh yes. I have a tremendous amount of Cubase .arr files I can't read, and heaps of floppies in various weird formats from old workstations that there's no easy way to read except by using the original hardware, which is slowly dying out (my second MV-30 gave up the ghost recently).
