I have the kind of GAS with 'exchanges disabled mode'. I'd only buy new (in terms of not having them previously, not the condition) basses, specific ones I desire, not every one and if I'm satisfied, I never sell them. The only bass I sold was Ibanez ATK310, for it was too modern for my tastes, and not too comfortable.
Within the last year I've bought three basses I've always dreamed of: Fender Precision Bass, Peavey T-40 and Fender Telecaster II bass (well, sort of). And while Peavey, a great player in fact, is a bit whimsical part of the collection, I'm quite sure the both Fenders are pretty much everything I need. But still I want to have 51' P-bass and Fender Jazz Bass and I'm sure I'd find a good use for them, too.