I have one I wouldn't do without. I use it to figure out how much backing to buy, how many binding strips to cut, and if I have a piece of fabric from my stash, how wide can I cut strips for borders. It is either in my studio or in my purse. Just Friday when a friend was over I used it for her borders, was wondering if i should get a second one, then I would always have one in the studio and in my bag.