you do not *have to have* the specialty rulers to make most blocks that offer them- but often they do make the job easier- and it kind of depends on who's instructions you are following- if you are using a pattern by Eleanor Burns it is going to be written with instructions for her ruler. each one works fine- but you need to follow the instructions for the one you choose- I have lots of rulers---and generally choose them by-finding them on sale- or wanting to use a specific pattern that recommends a specific ruler- I have rulers by Eleanor Burns, Marti Mitchell and Darlene --- they all work well for what they are designed to do. ...so go with the one recommended for your pattern or the one you find on sale- or make the block with a regular ruler & see if you think you would make these blocks again- and the specialty ruler would be handy- I do have rulers that I've only used once & they live in a drawer for years- no use- because they were for something I will probably never do again...those are not worth the $$!