Today while my daughter was wearing her new blouse, the elastic on one of the shoulders sprang loose from one side of the casing. Clearly I didn't sew it down well enough - maybe the stitching was too close to the edge. On each side, I sewed back and forth in a straight line two or three times. When I mended the elastic, I did three lines of stitching, back and forth, with the first and last line about 1/4 of an inch apart. Is this good enough? What do you do? I am new to sewing oft-worn kids' clothes and want to make sure I'm making them durable enough!