My stash was getting out of control, so I bought an Ikea 8-cube thingy that holds boxes. I put all of the stash that I had on a bookshelf into those boxes, trying to keep to specific categories. (I have a couple of shelves in a closet full of fabric too.) Well. The cleared bookshelf didn't stay clear for long because I started a new project and of course nothing in my stash was just right. Now the bookshelf is full again, the Ikea cubes are full, the shelves in my closet are full, and I find myself with a bin containing kids novelty fabric that has no place anywhere in my small 1-bedroom apartment.
That said, I like to sort my fabrics every 3 months or so because I suddenly decide on a new category and it's sort of like Scrooge McDuck counting his gold.