I am very slowly learning the hard way to not sew over pins. I recently did the most damage ever. When I hit the pin, it bent the needle which then stabbed into the side of the bobbin carrier. A great big slash in the side of it. My dealer didn't have a replacement one on hand, so I smoothed the plastic off with the blade of my scissors. (Yup, the sewing scissors). I have to replace them often too because I'm the worst offender of using them for things other than fabric.