If you used the edge of your presser foot for a guide for every piece in your quilt as long as you are consistent it should still be ok. It is just that if you are using a pattern say for a 12" block and you use the side of your foot for a guide the finish project may be a little smaller. I use to always use the edge of my presser foot before I got a 1/4 foot. My original foot was just a thread or two larger than a 1/4 inch foot.