If you're traveling to Europe or Asia, chances are you want to bring your iPhone along. As I discovered during a two-week trip through southern Spain, it's a good idea to do some planning in advance if you want to avoid humongous data charges and keep your device powered up. Here are a few things to consider before taking your iPhone abroad. \u00a0\u00a0\n\tYour normal data plan can turn into a cash-sucking monstrosity when you leave the country. A 1MB email can cost an astonishing $20 to download abroad, according to Verizon. Thankfully, you don\u2019t have to pay that much.\n\tThe iPhone has a very tiny SIM card that\u2019s easy to swap out. (Note the small tray on its side; pop out the card with a paper clip or similar tool.) All of your phone numbers, email addresses and the like are stored on your phone, so switching your SIM isn't a big headache. The card just connects you to the local carrier. The iPhone 5s and the 5c use a nano SIM, while older models use the somewhat larger micro SIM. Be sure to buy the right one and try it out in the store before you pay for it. \u00a0\n\tWhen I was in Spain, I stopped at a Vodaphone store and bought a SIM card that gave me 500MB of data and about 30 minutes of calling for 10 euros, or about US$13.80. That\u00a0was more than enough for me, because I wasn\u2019t making many phone calls, watching videos or streaming music.\n\tYou do, however, have to unlock the iPhone for it to work another carrier\u2019s network. You can pay some third party unlock your iPhone or simply call AT&T; the company will send a signal to your phone to unlock it at no extra charge. T-Mobile will do the same. New Verizon iPhones are unlocked when you purchase them. Unfortunately, Sprint won't unlock your iPhone, so you'll have to go through a third party, which voids the warranty.\n\tIn Japan, SoftBank will rent you a SIM for about a dollar a day, but data is expensive: roughly $15 a day, so you\u2019re probably better off using your U.S. carrier\u2019s roaming plan.\n\tA&T offers plans for voice, data and messaging, and charges vary by country. If you\u2019re going to Europe you pay $30 a month for 80 minutes of talk, which works out to 38 cents a minute. Data costs $25 for 120MB. Verizon\u2019s international roaming plan offers 100MB for $25, but the carrier charges $0.99 a minute for voice calls in Europe and an outrageous $1.99 a minute in Japan. In any case, be sure to cancel these plans as soon as your return home.\n\tWhile traveling, you want to use Wi-Fi as much as possible. Data downloaded via Wi-Fi doesn't count against your allotment. You may also want to make sure to turn off your \u201cpush\u201d email setting, so the phone doesn't automatically download messages and burn data. It's a good idea to keep a close eye on your data usage, which you can also find under \u201csettings.\u201d\n\tOf course, none of this matters at all if you can\u2019t recharge your phone. The easiest way to ensure you have everything you need is to buy the Apple World Traveler Adapter Kit (pictured above) for $39. It comes with adapters for nearly every region of the world along with instructions on which ones work in different countries. You can also use the adapter to recharge other devices.\n\tOne last word of advice: When using Apple's Maps app abroad, streets in smaller cities often don\u2019t appear in the app or appear without a name. Google Maps works better, in my experience, but it is far from perfect. So do yourself a favor and pick up an old-fashioned paper map to help find your way around those scenic, twisty streets.