If you need to cut several pieces of wood to the same length, here is a fast and accurate way to do it. Take a power miter box and attach it to a workbench with screws so it can't move. Cut first piece of wood to the desired length. Then hold the cut end of that piece of wood right up against the blade of the saw. Then take some scrap wood and create a little stop block right at the other end of the cut piece. Now when you make your next cut, you put the wood up against the stop block and saw. No matter how many of pieces you need to cut, they are going to be exactly the same length.