Elastic is one of the great inventions of the modern era. Think about it: We no longer need suspenders to hold up our pants, or garters to hold up our socks and stockings. Getting squirmy babies dressed is way less of a struggle. And the stretch of elastic makes clothing easier to wear — not to mention way more comfortable — whether you're sewing underwear, building bathing suits or constructing workout clothes.
Fact: your most comfy undies could very well be the ones you sew yourself. It's all about how you decide to finish your edges. (After all, nobody wants a pair that digs in!)