In my home shop I use a lot of home-made jigs, guides and templates. To make sure I am using the right edge or outline, I use colored markers or paint to make the edges and angles very distinct from each other. Too many times I have used a template upside down or on wrong side. Having the edges emblazoned with color is easier to identify than handwritten numbers and makes repetitive use a no-brainer.
– Bill Marshall
Omaha, Nebraska