If you are making clothes, stuff ravels. I've seen expensive costumes sewn with just a straight stitch and the fabric raveled right out of the stitching.
You could use pinking shears, zig zag, French seam, Hong Kong finish, rolled seam, or serge and keep it from raveling.
I've made kids clothes from Sew Beautiful - they are usually 1/2" seam. Kwik Sew uses 1/4" on knits. I've seen 3/8 at times. Things look neater without strings hanging out.