Keeping track of my important documents became a lot harder once I had kids, and my carry-on bag was full of diapers, wipes, and changes of clothes. A friend gifted me a passport holder that allowed me to keep my cards, cash, boarding passes, and passport in one easily accessible place. Beyond organization, a passport holder also protects your passport and gives stylish travelers the chance to make a statement with luxury materials, a range of colors, and personalized monogramming .  Passport holders come in a variety of designs, from simple covers to wallet-style holders with dedicated spaces for cards, paper documents, and even luggage trackers. We tested 17 passport holders from different brands as we traveled for six months, evaluating capacity, design, durability, and value. These are our favorites.…