how much you "waste" depends on how much of the cut-off portions you save. With all the renewed interest in strip quilts and crumb quilts, the conservative quilter will waste almost nothing in the long run, tho you may not use it all in one project. Art quilters can even use the thread pieces that come off...those less than a quarter of an inch, or the gnarly threads that occur when and if you prewash. Even selvedges are used today in projects. Also, do you cut individual pieces, or do you stip quilt? Strip quilting can often save fabric.