I also use Olfa green mats. I have had mine for over 10 years and it is still going strong. I try not to cut in the same area repeatedly and I think that helps. I don't use the lines for measuring but rather use a ruler so it is easy to move around the mat. I use the mat a lot and figure when one side gets too bad I'll just flip it over. At the rate it's going the mat may outlive me.