I buy the specialty ruler I don't have when a pattern recommends it. I keep the ruler with the pattern. The cost of the ruler is part of the pattern and project to me. I use the Block Lock rulers, and 10" square from MSQC a lot. I have every size square ruler up to 22". I don't use them much but when I do need them they are worth every dollar. Most of my cutting is done with my Go though. I have never found a ruler that cost more then a meal out and a movie.