I'm not sure that anyone really "plans" to have a stash. At least mine just sort of happened. I realized that I had a stash when it came time to sort the stack into colors (or values, or prints). When I had to put cabinets in the room JUST for the fabric, I knew that I had gone a little over the edge. But then I had more room in the cabinets so I got to buy more fabric. It's a blessing and a curse.
Right now I am in the process of loading my room again (we reorganized the cabinets) and my goal was to whittle down the stash. Darn it - I don't seem to be able to get rid of anything. Heavy sigh!