All negs in printfile. All under the customer name and in file folders and filing cabinets with 8x10 and smaller proof prints.
I have about 100 framed 16x20 and 20x24 prints that I rotate throughout different display places.
All other prints are in the handy dandy Ilford boxes unmounted and waiting for the day that never comes where I will dig them out. Unfortunately when I want another print I usually reprint it because I'm a better printer than I was a few years ago and I use different toning techniques etc.
I rarely do scenics but when I do I file them away in printfiles and file folders and wait until the rainy season and print some.
Not a real advanced system.
I do have all display or award proofs and negatives from my color days from 15-25 years ago stored in the same file folders only all together and not by name.