Jeans are pretty much the only universal uniform we can think of. They take you from brunch to baseball games, the office if you're lucky, and, heck yes, even holiday parties. They're no trend; they're the one look we know will never go out of style. Obviously, as the years go by, modern cuts and shapes hit the runway and are stocked in stores. But if you want a few ideas for how to avoid shopping new pairs at all costs, at least for the time being, you can refresh your old slacks in these 31 ways without a single worry that your outfit will look outdated.