Every once in a while I go back and listen to music I made 20+ years ago. I cringe a little at my less developed production skills and would do some things differently, but I also notice that I had some good ideas, and I can get a sense of how my tastes and techniques both changed and stayed the same over time. I wish that I still had my few even older pre-DAW recordings.
I also wish I still had my old journals I started writing in the 80s.