I'm in the same boat. I've only been acquiring a stash for about 5 years or so - mostly when I find a really good buy, but also when I see a fab that I've got to have. Some have specific projects in mind - some not.
This morning I went looking for something in my sewing room that I thought would be neat to FINALLY use on the landscape project I'm working on. 4 years ago at the IQS show in Chicago I bought a small bag of bits of green fabric embellishments - silks, fuzzies, ribbons - etc - and I wanted it NOW.
It wasn't in the first place I thought it would be so I checked the second place - a storage box under my sewing table. I could not believe how much stacked fabric I had to move to get the box out. I also found fabric I completely forgot I had. There was a time a few years ago when I could remember where I got each piece of fabric ... not any more.
My search was unsuccessful. No idea where this bag of bits has gone to.
The good news is that I cleaned and sorted the first place I looked for it (a small 2 shelf unit) and now all my books are sorted and properly shelved :)
A big project (when I'm done quilting the landscape) is to empty the closet completely and build shelves inside it so I can store fabric on boards standing up - then close the doors to keep dust and sun away.
So ... as of now ... I'm on a fabric diet.