A serger doesn't take the place of a sewing machine, it enhances your sewing machine. I don't use my serger for quilting, however, if I were to use tshirt or sweatshirt fabric for a quilt I would definitely use my serger for that. Generally, in quilting we don't bother to cover the edges of the seams, since they'll be covered with batting, and then the fabric gets quilted in addition to that. Sergers are great for garment construction, or any type of sewing where the seams will be exposed, such as curtains.
Christine-
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