Here's something that is food for thought. When you move the needle over your bobbin thread is pulled at an angle. This can cause imperfect stitching and tension issues. Libby Lehman just did a video for The Quilt Show where she discusses this and teaches about this in her classes. I had never thought about this, but it makes sense if you think about it. I have a 57 foot with guide for my 830 and will now be using it all the time.