For my first quilt I bought exactly what the rules said I needed, and had to buy another piece altogether (couldn't find what I had) and thus began my stash. My husband is a "pusher" and encourages me to buy fabric. He loves what I've done and realizes how happy I am doing it. He estimates I have several thousand dollars of fabric in my sewing room.
I do use my stash a lot. I have a system. My really small pieces are in a plastic drawer (one of those stack shelf units), the larger pieces that are cut into squares or rectangles fill another drawer. 8 other drawers are filled with smaller pieces of material (about fat quarter size), organized by colors. This really helps me use my small stash pieces as I sew.
I have yards of larger fabrics in my cupboard. A lot of them are music themed because I do a lot of sewing for an incredible boy boy choir (they have won emmys!). These will get used!
I have a lot of kiddie prints which I failed to use for my grandkids who are outgrowing them. These are finding their way to my church and to St. Vincent de Paul's.
I also have a lot of animal prints because I like to do "pictures" in my quilting. It can be very hard to find a certain dog, or eagle, or deer when it's needed.
I also have well several labeled boxes filled with a particular person or purpose in mind, and these include both large and smaller pieces.
The other larger pieces are, mostly, fabrics I see as very special to me and they are used constantly. I try to keep them by color (in general) but I plow through them regularly and have to set "clean up" days to get them organized. I keep them on the shelf folded so that the fold is out and I can see enough of the fabric enough to id it. By getting my stash in shape every few quilts it bring what I have to mind, and this helps me when planning the next quilt.
Since I can find the general place for the possible colors, etc. I find myself digging out several possibilities and, almost always finding the best piece for that emphasis I'm looking for.
And finally, we have exchanges in the quilt guild and there is always the Linus groups. Someone thought every fabric sold was good enough to be printed and sold, and often it is happily claimed by some happy quilter.
As long as I keep things organized I am happy and quilting like crazy. And yes, hubby and I do run off together, so we are both doing our thing!!!!
Sorry I'm so wordy, but this subject spoke to me! I'm going to keep my stash fat and me happy!