If you notice Fons & Porter's mat does not have lines. It was just mentioned on their show on Saturday. Many people flip them over to the other side after years of cutting on them and then there are no marks. Both sides are self healing so use the other if you don't want the lines. I use mine to line up things but use the ruler for measurements. I think it is whatever works for you. Either way the quilt police will not come after you.