auntlucy

I think that using the lines on the mat as a straight edge with your ruler to make that first straight edge on the left side of your piece of fabric (if you are right handed) is completely different from using the spaces between the lines on the mat as measuring units. The method I was taught in a quilt class was to use the lines on the mat to get your fat quarter, etc. aligned with the mat. Then line up the ruler with the mat line for that first cut only. From there it was ruler only to measure and cut the strips. This method requires that the ruler is placed on the piece being cut away from the whole. I agree with whomever pointed out that placing the ruler on the piece you are cutting prevents ruining the piece if your rotary cutter should veer away from the ruler.

grann of 6

I use the lines on the mat for squaring up, but use a dedicated ruler for the final cuts. Don't always trust the mat for the 1/4" markings.

SandyMac

I cut both ways it just depends on what I'm doing.

pieces

I use the lines on my mat when I am cutting strips.
But use a ruler when I cut my pieces from the strips.

Linda Loo

I've never had a "matching" ruler and mat! Therefore, the discrepancies between the two always made for chaos in putting anything together. I depend on my ruler. Never pay attention to the mat except to straighten something.

1barron

Out side of a cutting surface and doing a quick measure of fabric (that's what I use the mat for), I always use my rulers to cut.

thseabreze

I use both, the lines and a ruler

noveltyjunkie

I use the mat lines to make sure the corners are square, but I use the ruler to measure.

piepatch

I use my ruler.

champagnebubbles

I was taught to use my ruler, I try to do this.