1. Tipping: For airport porters, $1 per bag; for hotel porters, $0.5 to $1 per bag; for restaurants, 15% to 20% of the bill; tips for cloakroom attendants vary by location, generally 50 cents; for room service, 20% of the bill; for nightclub service, 20%; for taxi service, about 10% of the fare.
2. Voltage: 110-115 volts, 50 Hz.
3. Currency Exchange: Although there are many banks in the United States, very few offer foreign currency exchange services. Therefore, tourists holding foreign currency should either exchange it at airport exchange counters or convert it into U.S. dollar traveler's checks before traveling. Using internationally accepted credit cards such as American Express, Visa, or MasterCard is both safe and convenient.
4. Restrooms: Restrooms are available at gas stations, restaurants, and department stores.
5. Time Zones: There are four time zones in the United States: Eastern, Central, Mountain, and Pacific Standard Time. When it is noon in Eastern coastal cities, it is 11:00 AM in the Central region, 10:00 AM in the Mountain region, and 9:00 AM in the Pacific coastal region. To save energy, almost every state observes daylight saving time.
