How long before a passport's expiration should you renew it?

Travelers should renew their documents at least six months before they expire, according to the U.S. Department of State's Bureau of Consular affairs. Many countries require a passport to be valid for at least six months after a traveler's date of entry.

Passport processing times vary, but as of 2014, a routine passport application takes four to six weeks. Expedited passports are available for people who plan to travel within the next few weeks, but applicants must pay an extra fee. People who are traveling within the next two weeks should make an appointment to apply for their passports in person. If they have already applied, they can contact the National Passport Information Center.