I have been taking a ruler of the month class at my LQS here in Snohomish which has been very helpful. As others have said there is a learning curve to using rulers and practice is a must. As quiltedsunshine noted it is best to stop and check alignment often as it is easy to wander. Our class is currently working with border rulers and how to turn a corner on the border. I love these rulers and am totally addicted to them. The videos on YouTube are a plus but if you get an opportunity to see these in action at quilt show or shop you will be amazed.