I use to not wash but recently became a convert, don't know why. I think I like working with washed fabric better. I iron when I'm ready to sew since I use starch and don't want to invite bugs. Since I only recently started washing, I have a huge stash of unwashed, it's really getting hard to keep the two separated. I would not want unwashed and washed in the same quilt. My sewing room looks like a bomb went off. Only fellow quilters would understand.