I started playing guitar 20+ years ago, I always repaired and set up my instruments myself, fiddled with electronics, swapped parts, and even built one guitar from scratch (DIY neck, DIY bridge, custom pickup) and thought I knew everything.
It turns out being a bedroom guitarist I barely scratched the surface. Only last year playing in a band for 4-5 hours once a week showed me how much nuanced setting up an instrument could be.
I've made the nut for my 8-string (bought originally as defective, stock nut unusable) so long ago, that it was designed in a pirated CAD software on Windows, can't believe I used to do things like that :D
And only recently I found out how bad the design was. So I've made a good parametric
#OpenSCAD model, fine tuned to my needs, and printed it in polycarbonate.