It is best to apply for a passport several months in advance of your expected travel date. Alternatively, passports may be expedited by an Passport Service, but it can be expensive. If you do need to expedite your passport, be sure to bring a copy of your ticketed airline travel reservation with you, as well as other documentation. If you do have a passport, check the expiration date: some countries, like the 26 Schengen countries of Europe, enforce a strict rule that requires your passport to be valid six months after your travel return date! Your travel agent will need a copy of the photo page of your passport to book air and land travel arrangements.
The Smart Traveler Enrollment Program is free to United States Citizens traveling or even living overseas. It keeps you well-informed with the latest country safety and security information, including travel advisories. You are enrolled with the nearest U.S. Embassy or consulate thereby helping them to keep you informed and to assist family and friends to contact you.
It is always good to own a valid U.S. passport. You never know when the need or desire to travel might occur! Some closed loop trips, like Caribbean Cruises, do not require passport identification for check-in and embarkation. However if evacuation from the cruise ship for medical or family emergencies becomes necessary, a return to the U.S. may be impeded if you are not in possession of a valid U.S. Passport.