Like many of us here, at first, once I truly got bit by the bug, I "needed" all the knives. I bought in a frenzy, and as soon as a new knife arrived I was in search of the next.
Then I learned to slow down and enjoy the research process as part of the experience, and that helped prolong the jolt of dopamine that a new knife purchase brought.
Over time I learned what I liked, wanted, and (kind of) actually needed (or would get the most use out of at least). I justified each purchase by checking a box for a particular use, and tried to obtain the perfect knife for me for each use. I sold off many of my purchases from the aforementioned frenzy, and used the funds towards the purchase of fewer, somewhat higher end knives.
Now, I'm at a point where I just buy what intrigues me. If I see a knife I like, I get it. However, I feel it takes more for me to really want a knife than before, so I end up purchasing less. That being said, I still have fits of purchases, but I honestly don't think to much into it. Just fun and enjoyment.
Every once in a while I think "What does it all mean? Why do I spend so much of my finite time on this planet obsessing over possessions like knives and watches?" Then, in a few hours, the mushrooms wear off, and I'm back online obsessing about knives
Point being, just enjoy the ride, no matter where you are in the hobby.