Make sure you can easily see the markings on the ruler. I have one with black markings and I hardly ever use it because it's hard to see the marks on medium - dark fabric. I much prefer to use an Omnigrid that's the same size, because I can see the marks much easier. Some rulers are not necessary to make a pattern, others make it easier &/or faster. Probably every person on this Board have rulers they've bought and never used. Spend your money wisely.