I'm a little like this, but I do an "okay" job controlling buying in the first place and that helps. Once I have something, I have it for keeps, but I've reached a point where I see a new ruler/tool and I don't feel like I have to own it.
Even fabric...I don't buy on a whim nearly as much as I did when I started out. I still do a little, but much, much less than when I was a newbie and was still 'stash building'. Now I have what I think is a good sized stash - big enough for variety but not overwhelmingly large. I have it stored so that I can see everything at once so I always have a pretty good idea about what's in there.
But the things I DO have...those are MINE and I'm not getting rid of them, even if I almost never use them.