Some credit card companies recommend that you notify them of any impending trip abroad so that they don’t become suspicious and block charges when the card is used numerous times in a foreign destination. Even if you don’t call your credit card company in advance, you can always call the card’s toll-free emergency number, if a charge is refused—a good reason to carry the phone number with you. But perhaps the most important lesson here is to carry more than one card with you on your trip; a card might not work for any number of reasons, so having a backup is the smart way to go.