I've come to the realization that I need a seam guide in place if all my seams are to be accurate. I can sew accurately using the mark on my machine when I'm bright eyed and bushy tailed but after a while I get tired and my seam wanders a bit. That being said, as long as all my seams are consistent, even if they're a bit off the 1/4 mark, I don't worry. I've never made a quilt to be a certain size...it is what it is.