If you don't have an unlimited wireless data plan and sometimes even if you do you should pay attention to which apps use the most data on your iPhone.
Sometimes, for example, an app that you use frequently might consume far more of your data than you think. In my case, I found that Twitter uses nearly as much as Apple Music, for example. And, if you start to get warnings about using too much data, it could be that a buggy app is using more than it should.
It's good practice to check up on which apps are using most of your data. That way, you'll know to remember to connect to a Wi-Fi network when using a particularly data-hungry app, or which apps to limit before you go over your cap.
It only takes a couple of seconds to check. Here's how to do it on an iPhone, though the process is relatively similar on an Android phone, too.
Now you'll see a list of the apps that use the most data. If you click the "Last billing period" tab, you'll see what hit you most last month. This is the most accurate representation of which apps eat your data, since it includes a full billing period.
On my phone, I see that last month the App Store used up 10.5GB of my data. To save data this month, I could make sure that I'm only using the App Store when I'm connected to a Wi-Fi network, instead of downloading apps when I'm out and about.
Pro tip: On the same cellular settings page, you can see how much data you've used so far in the current month. If it's far below what you pay for, say something around 3GB when you pay for 10GB per month, then consider adjusting your wireless bill to save money. Or, if you're using far more, consider signing up for an unlimited plan. Just know that most unlimited plans aren't actually as unlimited as they say.
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