The mat really makes a big difference...I have said it before somewhere on here. But here is my experience. I had the original white mat...or maybe I should say one of the first white mats. The ones from Joann's. Well, I was going through rotary blades. Too many for the amount of cutting I did. But I was working and didn't even consider the mat. Then was at a quilt show, and got a newer mat...another white one. I liked the lines on it better...just wanted something new.
When I started with it, put a new blade in. I was not getting clean cuts. Somewhere along the way I had bought a medium sized green one...not sure of the brand. I had it by my sewing machine. I moved it over to my cutting table and was simply amazed at the difference. I don't sew every day...for sure don't do a lot of cutting most days. But my rotary blades last forever now. Keep in mind, when cutting strips, I use the 60 mm rotary cutter. They last longer than my 45 mm ones that I use near my machine for trimming crumb blocks, etc.
The one thing for accuracy...I place my hand on one end and cut to about midway of the 24 inch ruler. I make sure I stop cutting and then lift my hand from the ruler and place it farther up the ruler. Sometimes I walk it up, but feel the thing that makes the difference is to really stop cutting before I move my hand. It is a thing of actually thinking 'stop' and then moving my hand. This might sound silly, but it really helped me.