I use blue painters tape on my rulers to help me remember which line I am using as a guide , like when using my 5 x 24 ruler for cutting long 2 1/2 inch strips, I just put the edge of the tape along the 2 1/2 inch line on the underside of my ruler. it makes it easier to find the correct line each time plus the tape acts like a non skid and keeps my ruler from shifting while cutting ! Double bonus !