I agree with Rhonda K, it depends on the project. When I am stitching blocks, and matching up seams, quarter to half speed for me is plenty. I have been make lots of jelly roll rugs and table runners. When I am sewing the cord for them, I stitch full speed, then when they are zigzagged together, again full speed after the first few rounds. There is a rhythm to this type of project when at full speed, but for me, slower is better when piecing.