I prefer tearing my lengthwise strips. I usually allow a few threads more to allow for the threads. Once the two or three threads have pulled off, they're done. I press before stitching and the "little fringes" don't bother me. But tearing on the WOF is not always so good. If the fabric has been heatset at the factory off grain, then there is no pulling it back into shape. So I just square off the ends and cut across. I don't look at quiliting as rocket science, so as long as my pieces are fairly decent, I'm happy.