I have never mastered the 4 fold method of cutting a full length of fabric, so for me the 18" length would be a bit awkward. Too short to cut a full length, but too long to easily maneuver for general cutting. Having said that, however, it would be very convenient to have those standard widths available and not have to measure each time. If you want to get these, I would purchase them as you go for specific projects, or get the sizes you have used the most in the past. I've only had 1 quilt which called for 1/16" measurements and I just eyeballed the middle of the 1/8" marks.