I think the two most used ruler in my collection are the 6 X 24 inch and 6.5 inch square on. These I use all the time. Over the years I have added others, but those two are the ones most used. They are big enough but not too big. If I could only have 2, these are it. Of course, by now, I have a whole tote bag full. Most I do use on occasion, some I haven't used much at all.