If your passport is getting full, be careful. Some countries require you to have two or sometimes four empty pages available before allowing you entry. Airlines have the right to refuse you based on empty pages, so check with the embassies or your destination countries before departing. You can get extra pages from a U.S. passport office before departure.
U.S. passports obtained after the age of 16 are valid for 10 years (and those for people aged 15 and under are valid for five years). Consider the remaining validity of your passport before traveling. Some countries require your passport to be valid for up to six months upon entering the country (to coincide with the length of some tourism visas). The Department of State recommends renewing your passport about nine months before it expires.
While normal wear and tear is expected and acceptable, significant damage to your passport is a problem. If the first page (with your photo and personal information) is worn beyond recognition, you might encounter difficulty at customs and borders. The State Department requires people with damaged passports to report in person to a passport office with their damaged passport to have new one issued.
