Unless you're a Sprint customer—or you're grandfathered into an unlimited data plan—you've only got 2GB of mobile data to play with before you go broke or get throttled. Here's how to keep from going over your cap.
The consequences of using more data than your carrier wants can be scary—and expensive. AT&T and Verizon start charging $10/month for every 1GB over the cap you go. T-Mobile won't charge you, but they will throttle your connection to all hell, which for some people is worse. Sprint? Well Sprint is unlimited, so woohoo for that.
But whoever your mobile overlord might be, there are plenty of ways to escape its clutches.
Start with the moment of truth: When you find out what kind of Internet hog you've become. Sign into your mobile carrier account (AT&T, Verizon, T-Mobile) and check your data usage. If you're like most people, you're churning through less data than you think. But if you're like me and your data fluctuates between 400MB one month and 1.6GB the next, you should get ready to start pruning some of your habits.
To keep a semi-accurate account of your phone's data usage while on the go, carriers have apps that track your data usage. Well, everyone but Sprint, but again, unlimited. For everyone else, download your carrier's free usage apps: My Verizon (iOS, Android), myAT&T (iOS, Android), or T-Mobile My Account (Android). Knowing how close you are to maxing out is the easiest way to avoid it.
Find free Wi-Fi. Yeah it seems like a no-brainer, but if you're in the habit of ignoring hot spots when they pop up on your phone, you're doing yourself a disservice. Coffee shops, restaurants, even some bars offer free Wi-Fi to their customers. And it's silly simple to find these networks near your work or home and add them to your list of trusted networks.
In iOS, just head to Settings > Wi-Fi and and turn on Ask to Join Networks. When a network is nearby, you'll be presented with the the option to join. Those without a padlock are open networks. For Android, can download an app to quickly locate free Wi-Fi nearby. Wi-Fi Finder from JIWIRE looks promising.
Side note: it's good internet citizenry to patronize those establishments. They give you Wi-Fi, you buy a few drinks now and again. The circle of life.
If you spend all day browsing the Internet, I have some good news. Browsers like Opera Mini (Android, iOS) use server-side compression to make browsing faster and, more importantly for our purposes, up to 90% less data-intensive. Opera Mini will even show you how much data you're actually using while browsing. There's a privacy trade-off here—everything site you visit goes through Opera's servers, which means some circuit boards in Norway are very attuned to your browsing habits—but it's worth it for the real data hogs.
Also: whether you use Opera's browser, or the browser that came pre-installed on your device, use the mobile version of a site whenever possible. It'll be way less data-intensive by design. If your browser doesn't auto-load the mobile version, just add an "m" to the front of the url. For example: m.gizmodo.com.
Nothing will sneak up you faster and eat up data than streaming music from a subscription service. This is especially true if you have no Wi-Fi access at work, or you have a long commute and you plug your smart phone into your car stereo. I've personally seen my data usage jump from an average of 300MB a month to 1.5GB over a three month period on an iPhone with an Rdio account. That's dangerously close to the 2GB cap most carriers have imposed.
Before you start tuning into the angry rantings of talk radio on your commute, with a few adjustments you can still listen to your favorite songs while commuting. Mog, Rdio, Spotify, and Rhapsody all allow you to download songs within their mobile apps for offline listening. The app-based services can cost up to $10/month, but for heavy users that's still preferable to getting a huge bill because you couldn't stop listening to Party in the USA.
Watching a few music videos and an episode of Star Trek probably won't put you over the edge; watching all three seasons of Arrested Development over the course of a month almost certainly will. A three minute YouTube video will eat up 5.5MB while a 22 minute Netflix video will suck down 105MB. But if you use YouTube's mobile site instead of the app, you can turn off high-quality videos with the tap of the HQ button.
Netflix doesn't have that option and auto-detects your connection to serve you the highest quality possible. Because of this, you can burn through your data if you're not careful. Find a Wi-Fi spot before launching the service, or rip DVDs to your device.
Background Apps and Services
You have items on your device that are sucking up bandwidth in the background. Most of these activities have little impact on your data usage. But running multiple services at once not only dings your battery, it can start adding up bandwidth-wise.
On iOS, Notifications are constantly checking for updated information. To keep track of what apps are utilizing the feature head to Settings>Notifications. If you have Push turned on for your email accounts, your device is always checking for new messages. Head to Settings > Mail, Contacts, Calendars > Fetch New Data.
On Android, you run into the same issue with sync. To manage your background data exchange, navigate to Settings > Accounts and Sync and deselect Background data and Auto Sync. If turning Auto Sync off is too drastic, you can manually manage accounts. In fact, it's a good idea to check the Auto Sync setting periodically to see which apps you've installed are eating up your data.
Battle Data Hogs
Even with all the precautions, all it takes is one rogue app to burn through your data. To help you keep track of what your apps are doing on both platforms, check out Onavo (Android, iOS). Like the Opera browser, Internet access is routed through their servers and optimized for your device. This brings up the same privacy issues that could throw some people off, but if you're interested in data savings and you like looking at graphs of said savings, you should check it out. For iOS it's AT&T only right now, but the developer is working on Sprint and Verizon-compatible versions.
Apple's personal assistant for the iPhone 4S needs to connect to a network to give you all those tidbits of information you desire. Ars Technica did a thorough test of how much data Siri uses while checking on your queries and unless you're hassling Siri dozens of times a day, you should have nothing to worry about.
Stick With It
If you find any of these means drastic, remember that most people never hit the caps on their data plans. With Wi-Fi so prevalent at home and work, unless you spend a large portion of your days on the road, you should be fine. But, that doesn't mean you shouldn't be careful. A few simple changes can be the difference between enjoying Internet access on-the-go, and wondering if Top Ramen is a suitable substitute for actual food every time the phone bill arrives.
You can keep up with Roberto Baldwin, on Twitter, Facebook, and Google+.