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Turn Off Cellular Data
In Berlin, I opted to only use Wi-Fi on my phone. I wanted to make sure that I wouldn't accidentally receive calls, texts, or emails abroad, so I turned off cellular data. Here's how to do that on the iPhone 5: Go to "Settings," then "General," then "Cellular," then "Off." This turns off all cellular data and restricts your phone to Wi-Fi, meaning any emails, web browsing, and apps will only use Wi-Fi, not cell-phone networks. This is a really important step, as most smartphones automatically pull in emails, app updates, and other data-hungry things—and you don't want to pay for that!