Even though passports are issued for a hefty 10 years at a time, travelers still run the risk of a passport expiration abroad. Especially for those who travel frequently and for extended periods of time, your passport deadline may occur while abroad. If this is the case -- whether through last-minute travels or through oversight alone -- it is best to go through the steps to renew your passport while abroad (through a US embassy) instead of attempting to re-enter the US with the expired passport, as entry may be denied.
Depending on your destination country, make sure you have all the proper documentation before or upon entry. Failing to produce the correct documents when trying to leave can result in some difficulty. For example, multiple countries in the Middle East have strict rules about travel to other regions in the area, and there are different types of visas associated with multiple-destination travel. Travel to Syria, for instance, requires a visa beforehand, but if you plan on adding additional trips to Lebanon or Jordan, a multiple-entry visa may be required. Producing the incorrect visa will result in problems when trying to leave the region.
Some countries require a tariff, or fee, paid in full before exiting the country. Some countries, like Egypt, require this fee paid upon entry which typically is documented in your passport, and shouldn't cause any trouble upon leaving. Other countries, like Mexico, require this fee to be paid before exiting the country. If you've entered Mexico by land, this fee can be paid at any bank and then the receipt is presented upon leaving. If you've traveled by air or cruise, the fee will be included in your airfare or cruise fare and won't present a problem upon leaving the country.
Be wary of what you bring home from a foreign country or try to carry through a foreign airport. There are plenty of items that you can pick up at markets or bazaars that don't travel well through security. In Prague, there are various markets that sell "ninja gear," like throwing stars and brass knuckles, which seem like interesting souvenirs, but are considered illegal weapons and will not make it through airport security. Transporting certain food items from a foreign destination back to American soil is sometimes frowned upon; always check rules and regulations before you try to bring something back with you.
While this is liable to occur during any trip, domestic or abroad, an unexpected flight cancellation, broken bus or delayed cruise ship can severely impact your return trip. Usually if it is the fault of the transportation company, you can rearrange your travel plans at no cost. However, if you miss a flight due to a late bus or otherwise delayed method of transportation, be prepared to spend some time rearranging your travel plans. Patience is a virtue when smoothing over travel plans gone awry, so if you find yourself trying to re-book a missed flight in a foreign country, remember to stay calm.
