We save anything 1.5" by 2.5" or larger. Our plan is to use the 1.5" strips for a pineapple quilt. I'm wondering if we should go to 1" square. That is the traditional size for postage stamp squares. If you think you would ever make a quilt with these tiny pieces make that your minimum and start saving. I would recommend that you cut all your leftovers down to usable sizes as you work on your quilts. As others have said, it is much harder to cut them up when you have a huge collection.