crumbs can be fun.....anything bigger than 1 inch by inch I would keep as a crumb....(figure a quarter inch seam on every side leaves you with a 1/2 square if you use a one by one inch piece...which I think is pretty small....but if you want to use a 3/4 by 3/4 piece....you will get a 1/4 inch square finished....pretty cute....but labor intensive and makes for a very bulk and heavy quilt as there would be more fabric in the seams then on top....one fun idea is to make the crumb blocks by color....eg...put all the blues together to make blocks......then all the oranges...etc.....have fun...let yourself go...you don't actually need to know what the finished quilt is going to look like when you start sewing the crumbs together.....