I took the scrap therapy class and she recommended to cut scraps into squares: 2", 3 1/2" & 6 1/2". Her rationale is that if you make a 4-square block and use the 2" squares, that block would equal 3 1/2". If you do that 4-square pattern and use 3 1/2" squares, that would equal a 6 1/2" unfinished block. I also like 5" - nickel sqyares so I have some of them in my plastic shoe boxes. But, I don't usually cut up useable yardage into the squares, I only reuse scraps. The fact that I make a lot of scrappy quilts means I usually have a lot of scrappy squares to work with. And....she pointed out that you pay as much for the fabrics in your scrap pile as for the ones actually used in quilts....so now you're getting something for nothing. I have made 10 scrap therapy quilts using only those pieces I would have thrown away if I were in a fit to clean out my quilt studio.