I have to add one thing that I have not seen anyone comment about. Unfortunately, I am a perfectionist. I just started quilting last Fall. I took a class at our LQS. I was cutting away on the project for the class and measuring everything then doing the 1/4" seam checking that over and over. I could not figure out why the stips were a little different. The teacher came over and watched me. All seemed to be right but she tried it and the cutter did the same thing to her. She opened it up to look at the blade closer and it was packed with lint from some fleece I had been cutting. It was causing the blade to wobble just enough to mess things up good. She cleaned it out, tried it again and it was perfect. So you can be doing everything right and some little nuisance thing like that can throw you off.