Interesting question to pose, and it's eliciting a lot of introspection and confessions!
As to me, I brought a sword back from a trip to Japan 25 years ago and became hooked. I entered an intense phase of study and put together a sizable library of books on Nihonto. I shortly thereafter entered a phase of "buy and sell" in which I ran ads, ran around like a nut buying swords and sold swords to Japanese dealers and collectors for several years. I had to continue to study then so as not to "buy high and sell low", so the books became even more important. The only sad part about that phase is that I had to sell all the very best swords that I got since I couldn't afford to keep them, so my actual collection consisted of mostly the lower end pieces.
The last 10+ years, I have not sold many swords and have primarily been a collector, but I have to confess to being an accumulator as well. I have bought a lot of gunto with hand made, usually koto, blades in them and have just tucked them away. I can sometimes kantei them and sometimes not. I am a scientist in my professional life and am in the business of creating new knowledge. I became a bit frustrated with studying about nihonto constantly because I felt that I was only learning what is already known and not generating any new information.
Presently I enjoy reading books on kantei and the NMB and am still picking up swords, mostly on ebay.