When I 1st learned to quilt, it was because I won a free class. I knew nothing, so I did not learn any bad habits. I was taught to use the ruler.

The lines on my mat are consistent with the lines on my ruler and so I do use my mat all the time.

For those of you who want to see it done, try looking on you-tube for squaring up fabric or rotary cutting with rulers. I'm sure there are many demonstrations on there.

I use the lines on my mat to square up the fabric, but I never "measure" fabric with those lines. I was taught to stay with one brand of ruler because even rulers can vary and certainly a mat would be even less accurate. I always use Ommigrid rulers only because that's what I have the most. I use other specialty rulers for angles, special projects, etc. I also use an Olipfa ruler as my straight edge with a rotary cutter because I like the stability I get from "hooking it" onto the edge of the mat. An additional aid, for me anyway, is the Gypsy gripper. My rulers seem to slip less when I use the gripper on the straight edge I am using as my cutting edge.

Would you post again what you are talking about because I don't understand either?

I use both

I also use both. I wouldn't do it any other way. I love both the rulers and the measurements on my mat.

I was using the mat most of the time....just using the ruler for a straight edge to cut against. I've been forcing myself to use the rulers now as I think that is more accurate for me.

I'm confused, I use the lines on my matte how so you not?

I googled cutting fabric from first cut. There are so many videos, I watched two of them, one used the lines on the mat and one used the ruler. Hmmmmmm