Having a big stash sometimes sounds like having a badge of honor..... but it isn't unless you have a plan for all that fabric. I agree with so many here that say, don't buy just to have fabric. I've been quilting going on 30 years now and believe me when I say, 'stash happens'. If you buy for the projects you plan to make, you'll still start adding to your stash and before you know it you'll have STASH!! I try to use up fabrics from my stash as much as possible but there are still some pieces that I think I'll never use. .... until styles change and then I might be very glad I still have it.
If I find a fabric I just 'have to have'.... I buy 3 yards. That's usually enough for borders plus some in blocks. Backings usually require 5 yards if you use 40-42 wide fabric. And, I bought 2 10-yard bolts of fabric this summer for a couple of quilts so I'll have enough for the background blocks of applique. So, I always have a plan.
Patience is often so hard to come by..... it's works when buying fabric, too.