I use the rulers to cut with mostly. If it is a big cut, I will use one of the marks on the mat to line up the cut edge. I do have a 15.5 inch square ruler so I can go pretty big with the ruler and I have also two rules to measure butted up sometimes. One trick I learned with the rotary cutters is not to tighten them too much. If you adjust the screw so it is tight enough so the blade doesn't wobble but loose enough that the blade turns easily as you push it along that mat....that is good. You don't want to have to use a lot of force to just get the blade to turn without doing any cutting. Oh, and new blades are good. I try and get mine in the multi packs when they are on sale. My local chain stores keeps the multi-packs locked up so sometimes I have to ask if they have any.