I don't agree with the flannel is tough on blades. I sew a lot with flannel. Matter of fact probably 90% of the time. I do agree with the hitting the blade just right on the ruler will pit the blade. I've done it. I have metal 3 and 4ft rulers as well as wood and a 18 in plastic quilters ruler. With the wood...I've accidentally shaved it down here and there. The plastic(acrylic)...Never an issue. But the metal...Well even though they are my favorite, I have to be very careful how I cut. Those are the ones I pit my blades with. Not often cause I've learned. I don't have much space so I put my cutting mats on my ironing board. I used to always cut on the floor also till I got smart. My knees started hurting. Ironing boards...Quick up...Quick down. The boards can have groves but at the most it can make the blade skip. If you get a "GUM" eraser and run it in the groves in the mat, it will help reseal and extend the life of the board.