I'm also an ebb and flow collector, though in the grand scheme my collection has gotten significantly smaller over the past couple years ...
Since I collect traditionals as well as tactical/modern knives, that adds a level of complexity ... with traditional slipjoints in natural material handles (bone, stag, wood), you truly are selling one-of-a-kind knives when you let those go ... much harder than say a PM2 that you know you can replace later ... especially when you land a particularly special one ...
About two years ago, I had 200+ traditionals, the vast majority of which were GECs ... all were very meticulously "screened" when purchased (zero blade play, well-matched scales, etc, etc), so this collection had taken a considerable amount of effort to acquire ... and then, one day ... I did the math. There were just too many "safe queens" sitting around ... so I started selling them off, a handful at a time. Very tough decisions on which to cut, and some I regret letting go to this day, but just couldn't justify all that "jewelry" just sitting there ...
So now I'm down to around 45 traditionals and around 35 modern folders, and I'm feeling the itch to thin the herd some more ...
It will likely be mostly "moderns" that go though, because as I said, the others are harder to come by, and those have been pared down to the dearest of the lot ... but meh, maybe I can let a few more go ...