I never wanted a stash but then ended up with one. The only time I find it helpful is doing applique when you need a speck of something.
Yesterday, I dumped all my "stash" bins into a big laundry bag. It will sit there for a few months and if I dont use it I am getting rid of it.
I counted my UFO's and I have 14 that's enough for now to work on.
Like one person said, my tastes change or I can never find that 4th fabric .
I am using my stash to learn to FMQ but muslin is a whole lot cheaper than LQS fabrics.