I use the ruler lines, I do use the lines on the mat for lining up the fabrics. I believe I read somewhere NOT to use the lines on the mat for cutting. But, in 10 months going through a mat is pretty bad, do you have a new blade in? Are you pressing harder than you have to in order to cut? It takes me 2-3 years in cutting before I even start needing to think about getting a new mat.