I pulled out a few of my sewing books. I think there are specific times you might want to sew then serge versus sewing/serging at the same time. I'll have to do more investigation into this as I am quite a newbie serger. One thing my sewing instructor suggested when I took a class at Saddleback was to go to the department store and see how commercial garments are put together. I think it is a good suggestion.