Suitcases are tight quarters. One dirty sock or wet bathing suit can turn an entire vacation wardrobe into a dirt-smeared, olfactory mess. Don't make your clean clothes rub elbows (or knees, or feet) with your dirties—pack a small laundry bag that can contain wet, soiled, and smelly clothes. A simple grocery bag will do, but if you want to get fancy you can also find reusable options such as Flight 001's resin-coated Go Clean Wet Suit bag. And if you forget a bag, check the closet of your hotel room; many still stock a plastic bag for in-hotel dry-cleaning services.