I used to keep every bit - just like my Mom - Now I only save certain pieces - since I like to do strip quilts I cut my leftovers into 2 1/2" strips or if there is enough to cut 4 1/2 squares I do that. So right now I have 2 "scrap bins" one for the strips and one for the squares. If I get into applicay (sp?) later I will start a 3rd bin with odds and ends.
One thing I think is important - no matter what you save - what size your stash is - 2 times a year go though yourfabrics and weed out what you are no longer intersted in - try to avoid becoming a pack rat. The is a certain joy in just owning fabrics!