ok, don't know if everyone will agree with me or not but...my understanding of sizing is just that, you use it for clothing that needs to be reshaped so to speak after washing it. Starch just stiffens everything up, but it's good when you need a crisp edge or detail on clothing. I don't know why your asking but I use sizing anyway when ironing my quilt fabic or pieces that I'm working on because it helps to get the wrinkles out without getting it all stiff. I hope this helps!