Turn off autoplaying videos on Facebook and Twitter
Our collective laziness loves not having to press play to watch whatever adorable puppy video shows up in our News Feeds, but that little feature is a huge data-eater. Simply turning it off can do a great deal to cut back on how much data you’re going through month to month. In your Facebook app, go to Settings > Videos and Photos > Autoplay > On Wi-Fi Connections Only. For Twitter, open the app, tap the Settings cog wheel > hit Video autoplay > select Use Wi-Fi only.
Stop apps from eating through your data when you're offline
There are some apps you absolutely want to be able to browse anytime, anywhere (lookin' at you, Facebook), but not every app on your phone needs access to your cellular data. Thankfully, you can individually toggle their access to data according to your preferences: head to Settings > Cellular and tick them on or off.