I serge the edges of my fabric before I prewash..that solves that problem for me. I find when I handle pieces more, I have more trouble with fraying. I try to only handle them/press them as needed. The age old wash/don't wash will be with us forever. (I wash because I had a quilt run ..yes it was GOOD fabric and I paid good money for it. The quilt was ruined. That fabric was washed ..and washed and WASHED. It never stopped running...so it ran into the TRASH!)