I did go through a rationalization exercise several years ago. I started with the basses that were cool to have, but that really didn't have much practical use for what I'm usually asked to do (ABG, EUB, 12 string, etc.). I had lots of special purpose 4 strings that went next (Ric, Stingray, Warwick, TF fretless, etc.). At that point, I still had at least 6-7 basses, all Fenders or better Fenders. I'm mostly a P bass guy, so any non-P's went next. The hard part came when I realized that I only every gigged/used 5 strings (down tunings for old vocalists are easier this way) - this meant that the 4 string Ps (there were several) had to go. This left me with a Canadian Dingwall AB2-5 and a Lakland Skyline 55-64 (5 string P). The Dingwall was an amazing bass, but after a problematic gig, I stopped taking it out, so that had to go, leaving only the Lakland. In the end, this was the one that was getting all the playing time, so it made sense. It was painful, but I was glad to free up the money and space. Having one bass provides some standardization, which helped me improve a bit (no more switching around between instruments). Ultimately, I felt bad having so much gear while only being a pretty good player. I thought that my #14 bass might just be someone else's #1, so better to have it end up there.