Stopping five data-hungry apps from killing your data plan isn't the only way for iPhone owners to reduce their data usage. There are five phone-wide settings that can help keep you under your monthly data allotment.
1. Disable cellular app updates.
If your apps update automatically, make sure they do so only when you are on WiFi. Go to Settings > iTunes & App Stores and turn off Use Cellular Data.
2. Disable background app refresh.
iOS apps can update in the background, grabbing new content as they sit idle so they can show you the latest news when you return to them. Go to Settings > General > Background App Refresh and you can turn this setting off completely or go the a la carte route from the list below and choose which apps update in the background.
3. Disable Wi-Fi Assist.
Wi-Fi Assist is a great feature where your iPhone hands off a weak Wi-Fi signal to your cellular network to prevent pages from loading slowly or not at all as it clings to the last remnants of a Wi-Fi signal. If you sit on the edge of a Wi-Fi network at work, say, then your cellular network may be assisting more than you'd like and running up data charges.
To disable Wi-Fi Assist, go to Settings > Cellular and scroll all the way to the bottom to turn off Wi-Fi Assist.
4. Disable iCloud Drive on cellular.
If you use iCloud Drive to shuttle documents in and out of the cloud, those data transfers can add to your bill if they are done over a cellular connection. You can restrict iCloud Drive to Wi-Fi only by going to Settings > iCloud > iCloud Drive and scrolling to the bottom and turning off Use Cellular Data.
5. Download music, don't stream.
Streaming music or podcasts for long stretches when you are away from Wi-Fi can quickly add to your data usage. Most music and podcast apps (like Spotify and Apple Music) let you restrict streaming to Wi-Fi only, which will then force you into the habit of downloading playlists or podcasts before playing them instead of the easy route of simply streaming them. Let's look at Apple Music and Apple's Podcasts apps as examples.
For Apple Music, go to Settings > Music. In the Streaming & Downloads section, you'll see two settings if the first is enabled. The first, Use Cellular Data, lets you disable streaming via a cellular connection entirely. If that's too drastic a measure for you, then you can leave that setting enabled and turn off High Quality on Cellular to stream songs at a lower bitrate when you aren't on Wi-Fi.
For the Podcasts app, go to Settings > Podcasts and turn off Cellular Data. You can also enable Only Download on Wi-Fi to prevent podcast downloads from adding to your data usage.
For more, see three surprising ways to lower your data usage.