I sure have enough rulers to keep me busy for a very long time. I have to admit that it is nice to have a " specialty" ruler as it makes the job go faster...and, of course, I've been known to grab the wrong ruler to use! That can really mess things up. I have a couple of rulers that have holes in the corners. What the holes are for, I have no idea. They are too big to make a mark with a small dot. Having the right ruler for the job is nice. It reduces the chance that I might make a measuring mistake.