I make a lot of knit shirts and camis for my daughters because I can make them custom length and modest. It is important to have a stretch hem so that the stitches don't pop. I also have a home sewing business and need to shorten hems on T-shirts for some of my customers. There are special (and expensive) sergers that have the coverstitch feature, which duplicates the stretch hem you see on most ready-made apparel. You can duplicate this at home with a simple notion, which is one of my favorite: The Double Needle.
