All things must come to an end. Including U.S. passports. But fortunately, they can be renewed. Kids' passports, issued before the age of 16, expire in 5 years; passports issued to those 16 and up remain valid for 10 years. You can renew by mail if you still have your expired passport and it's in decent shape, it was issued after you were 16 and within the last 15 years, and it has your current name or you can provide legal documentation of your name change. If you don't meet all these conditions – or if you're under the age of 16 - you have to renew in person and go through the entire process of having a passport issued for the first time.

Documents for Renewing by Mail

If you can renew by mail, download and complete Form DS-82, available on the U.S. Department of State website's page for passport forms. You also need to include your previous passport and any supporting documentation regarding your name change, if applicable.

The Department of State also wants a new 2-by-2-inch color passport photo taken within the last six months. Have it printed on quality photo paper. It should show your whole head straight on, with a neutral expression or natural smile on your face, and you should be wearing normal clothing and no accessories. And it needs a plain white or off-white background. Lots of post offices, county clerk offices, shipping stores and other passport acceptance facilities provide passport photo services.

And finally, of course, there's the matter of the fees. Don't forget to include your check or money order payable to "U.S. Department of State," or there'll be no renewal for you. The agency website has a passport fees page where you can get current information about how much to pay.

Documents for Renewing in Person

If you have to renew in person at your local passport acceptance facility, you need Form DS-11 instead of DS-82. Fill it out ahead, but only sign in front of the attending passport agent. You'll also need to bring the photo as described above and the applicable fees. And, if you're applying in person because you no longer have your last passport, also bring along Form DS-64.

You must also prove U.S. citizenship with an undamaged U.S. passport; birth certificate issued by a city, county or state government; certificate of citizenship; consular report of birth abroad or certification of birth; or a naturalization certificate. Plus, you'll need a black-and-white, one-sided photocopy showing both sides of the document.

Then there's the matter of proving your identity. Do so with an undamaged U.S. passport; current driver's license; city, state or federal government ID; military ID; or naturalization certificate. If you apply at an out-of-state facility and use a state ID, you must show a second form of identification. And again, bring a black-and-white, one-sided photocopy showing both sides of the identifying document.

Additional Documents for Renewing for Children Under 16

Technically, children under 16 can't renew a U.S. passport; they can only be issued a new one. The process is mostly the same as an adult applying in person, requiring the same documents, with a few extra ones.

Both parents or legal guardians must be present and show their identification, as most kids don't have a valid form, as well as proof of their relationship with a U.S. or foreign birth certificate, consular report of birth abroad, adoption decree, or divorce or custody decree. If one parent or guardian can't be there, they must give consent via Form DS-3053. Or, if one parent has sole custody, show supporting legal documentation. If one parent can't be located, fill out Form DS-5525.