This little vintage dress, which I thrifted for $1 then hemmed to above the knee, was just a tad snug on me. I could zip it up, but barely. So to give myself just a little extra breathing room, I unpicked the zipper, opened up the fold. And restitched the zipper in place, exposed. This ended up giving me an extra 1/2 inch on each side of the zipper, just enough to actually allow me to breath when I wear it. While this trick won't work if you have a dress that is way too small, it is a great way to just let it out a touch.