Q: When do I need to carry a passport?

A: Basically for all foreign travel, with a few caveats. Since 2009, the United States has required Americans to carry a passport or an accepted alternative when traveling to Bermuda, Mexico, Canada and 17 Caribbean nations. U.S. territories such as Puerto Rico, the U.S. Virgin Islands and Guam are exempt, as are cruises that begin and end in U.S. ports.

Children younger than 16 traveling to the above destinations by land or sea can still use their U.S. birth certificate (original or copy) or another proof of citizenship to re-enter the States. Also, U.S. passport cards valid for sea and land crossings (note: not air) are acceptable for travelers of all ages.

For application info, go to travel.state.gov/passport.

Acceptable alternative documents include Trusted Traveler Cards (i.e., Fast Cards), U.S. Military ID with travel orders and Native American photo ID cards.

Q: How much advance time do I need to apply for a passport?

A: It can never be too soon. If your passport is nearing its expiration date, renew as soon as possible, because some countries require passports to be valid for six months after a traveler's entry or return date. Passports issued to travelers 15 and younger are valid for five years, twice that for those 16 and older.

Q: Can I apply by mail?

A: Not if you're a first-timer. Mail-ins are for renewers whose old passports were issued within the past 15 years and haven't been damaged or stolen or haven't expired. The passport also must have been issued after your 16th birthday, and there must be no name change for which you do not have legal proof.

To renew a passport, place a DS-82 application form (available on the State Department website, at post offices and at travel agencies), your most recent passport, one 2-by-2-inch photo and a check for $110 made out to the U.S. Department of State in a padded envelope.

If your name has changed, also include a certified copy of the legal document specifying the change (e.g., marriage license, court decree, etc.).

Mail to National Passport Processing, P.O. Box 13408, Philadelphia, PA 19101-3408. If you use a mail service that doesn't deliver to post office boxes, send to National Passport Processing, Attn: Department 13349, 1617 Brett Rd., New Castle, DE 19720.

Your new passport (along with your old one) should arrive within four to six weeks.

Q: Who must apply in person, and what is the process?

A: You must apply in person if:

And, yes, even newborns and toddlers need a passport and must be present when their parents apply on their behalf.

Application materials include Form DS-11 (but don't sign it until the passport official gives the word); proof of U.S. citizenship, such as an original or certified birth certificate; personal ID, such as a valid driver's license or military ID; one 2-by-2-inch passport photo taken in the past six months; and $135 (16 and older) or $105 (younger than 16). Note: A law passed in April requires the full names of the applicants' parents to be listed on the certified birth certificate.

Q: Where do I apply in person?

A: There are more than 9,000 passport acceptance facilities nationwide, including many federal and state courts, post offices, public libraries, and county and city offices. See the state website (iafdb.travel.state.gov) for local outposts.

Q: What if my passport is running out of pages?

A: If you're down to two to four visa pages, you need to fatten up your book. Send your passport, DS-4085 form and $82 to: National Passport Processing Center, P.O. Box 90106, Philadelphia, Pa., 19190-0106.

Q: I'm in a hurry -- my trip is in a few weeks!

A: For expedited service by mail, send in the requisite materials plus an additional $60 and overnight delivery costs. Write "Expedite" on the envelope and put the departure date on your application. To ensure timely delivery -- two or three weeks door-to-door -- splurge on two-way overnight delivery.

If you're leaving in two weeks or sooner, make an appointment with a Regional Passport Agency. For even faster, but costlier, service, use a private company. For instance, American Passport and Visa International (866-848-2784, www.apvi.net) offers 24-hour service for $199 plus government fees; for delivery within six to nine business days, the price is $75 plus fees.

Other companies include A Briggs (800-806-0581, www.abriggs.com) and RushMyPassport.com (877-503-9838), among many others.

Q: Where can I find official passport information?

A: On the State Department website, travel.state.gov/ passport.

For a status report on your application, contact the National Passport Information Center at 877-487-2778 or check online at http://travel.state.gov/passport/status/status_2567.html.

Within five to seven days, the site will let you know whether your application has been received and about when to expect your ticket to roam the world.