Measure twice mark with a finger mark and cut with whatever

I dont often air mistakes but hope it helps someone that has not encountered this as I have. I wasted some material being very careful to measure accurately with my new birthday tape measure... you know the one with the magnet affixed to the dummy end. After several cuts in a poorly lit work ares I noticed I had varying lengths of material.

My wonderful new magnetic taps had picked up fillings and cuttings on the dummy end. Hope I save you some frustration and material.