I've gone through this cycle far too many times, the psychological weight of having more basses than you can 'justify' can become overwhelming, but realistically, unless you really need the money or the space, then just put a few out of sight and forget they're there for a year or two. It'll save you money in the long run - no need to ask I know that!
For me, the main pressure is space, I have enough wall hanging for 6 basses, but currently have 7, so plan to sell 2 I don't use and buy another Jazz Bass that I will. The pressure to keep the numbers down comes entirely from myself, my wife always tries to talk me out of selling any of them. Unlike some people, she welcomes new basses and I have to sneak older ones out of the house if they are leaving the family!