Remember, the only way to be sure your valuables are not damaged or lost is to keep them with you. Even if your bag is not lost, it could be delayed for a day or two. Check with the airline for its limits on the size, weight, or number of carry-on pieces. If you are using more than one airline, check on all of them. If you plan to go shopping at your destination and bring your purchases aboard as carry-on, keep the limits in mind.
Checked baggage is also subject to limits.
There can be an extra charge if you bring more, or if you exceed the airline's limits on the size of the bags. On some flights between two foreign cities, your allowance may be based on the weight of the bags rather than the number of pieces. The same two bags that cost you nothing to check when you started your trip could result in expensive excess-baggage charges under a weight system. Ask the airlines about the limit for every segment of your international trip before you leave home, especially if you have a stopover of a day or two or if you are changing carriers. Add the name and address of a person to contact at your destination if it's practical to do so.