The end of 'unlimited'

Americans like living large. We have all-you-can-eat buffets and all-you-can-stream entertainment. And, until recently, we had a virtually unlimited trough of mobile data to digest on our always-available smartphones.

At this point, even though, all however one of the major US carriers now limit smartphone data usage somehow or other. AT&T and Verizon charge if you go over your allotted number of bytes, during T-Mobile slows your speed down to a crawl once you've crossed its carefully measured line. Only Sprint continues to offer really unlimited data plans to new subscribers.

"This trend is happening all over the world," says Thomas Husson, a mobile analyst at Forrester Technology. "Carriers need to monetize their core assets and avoid the risk of a few users saturating their networks."

As the era of limits on data usage enters its second year here in the US, it's worth taking a look at how tiered plans are actually affecting smartphone users. Can we make it through an entire month with only 2GB of smartphone snacking, or should we spring for that beefier 5GB plan? How much mobile data do we in point of fact need, all the same? And what can we do to avoid that dreaded "data overage" line on our straightway cell phone bill?

The state of the U.S.

Let's start with the state of the U.S. smartphone data market. The prices vary a bit, however when you round to the nearest whole number, you're at heart paying about a penny per megabyte on the major carriers' current monthly data plans.

The lower-end options, in the meantime, are more expensive by the byte: AT&T offers 300MB for $20, which comes out to about 7 cents per megabyte, during T-Mobile offers 200MB for $10 -- or about 5 cents per megabyte. Verizon doesn't have a lower-end plan for smartphones.

The major US carriers

None of the major US carriers was able to provide me with specifics about average usage on their networks or the percentage of clients subscribing to each data plan, nevertheless independent analyses can give us a pretty good picture of where things stand.

According to The Nielsen Company, the average per-user data consumption by US smartphone clients was 606.1MB -- or about 0.59GB -- per month in the third quarter of 2011. That's an increase of 39 per cent from the per-user monthly average in the first quarter of 2011 -- and a whopping 80% jump from the per-user monthly average in the third quarter of 2010, just one year previously.

The data measurement tools available in Android 4

Using the data measurement tools available in Android 4.0, a.k.a. Ice Cream Sandwich, I carefully tracked the amount of mobile data consumed by a variety of common smartphone tasks.

First, I tracked my total data usage over a full day in which I engaged in relatively heavy Web browsing and social network activity, along with regular email usage and RSS-based feed reading. All of that combined -- and as well factoring in any incidental data consumption throughout the day, just as app updates and the few kilobytes used here and there by the operating system and random applications -- resulted in a grand total of 30MB of data transferred for the day. That kind of usage would add up to a month-long total of just 900MB -- not even a full gigabyte -- if it stayed consistent over the course of 30 days.

Of course, we use our smartphones for more than just basic browsing. So I as well measured the amount of data used in an hour of high-quality music streaming via Pandora. That burned up about 32MB of mobile data -- meaning that, if you streamed a full hour of high-quality music and engaged in heavy Web and social network usage every single day, you'd all in all be in accordance with 2GB for the month.

How small of a number are we talking about?

How small of a number are we talking about? According to an analysis conducted by Nielsen in the first quarter of 2011, only the 97th percentile -- the top 3% of all smartphone users -- exceeded 2GB of smartphone data usage per month. Within that subset of users, but, the level of consumption is huge: For instance, the top 1% of users devour a hefty 4.5GB of mobile data every month, according to Nielsen's measurements.

It isn't only the most extreme cases that result in hefty fees, even though. Just ask Thomas Brewer, a medical billing specialist who uses his phone for Web browsing, music streaming and the occasional Netflix video. Brewer says he passes his 2GB limit with Verizon nearly every month, by and large by a matter of mere megabytes.

Robert Finley, a software engineer who likes listening to podcasts on his phone, recently upgraded to a high-tier plan in order to save himself a headache. Even though Finley has never in fact gotten a penalty from his carrier, he grew tired of nervously watching over his shoulder to make sure he didn't exceed his cap.

Use Wi-Fi whenever you can. At the office? At home? Toggle your phone's Wi-Fi mode on, and you'll avoid unnecessary 3G/4G network usage. Do the same in the ever-increasing number of public places with free Wi-Fi, just as retail stores and coffee shops. Just remember to be extra cautious about security when connecting to any unencrypted public network.

Android device

If you use an Android device, there are several apps that can automate the process of accessing Wi-Fi networks; they'll switch your phone's Wi-Fi on when you enter certain locations and turn it off when you head out. I like Tasker, which is available for $6.49 in the Android Market. Setting Profiles, which costs $3.99, is another good option.

Watch your background data consumption. A lot of apps, ranging from social media programs to news-reading utilities, check into cloud-based services to look for new updates while the day. Find the background data settings for relevant apps and disable or dial back the settings on things you don't need. Taking everything into account, if your phone polls Facebook for new messages every 15 minutes, that activity can add up over the course of a month.

Set limits on your mobile data. Smartphones are getting smarter about helping you track and control how much data you use. Android has an integrated data management tool in its Ice Cream Sandwich release that allows you to view and restrict each app's data usage, set warnings based on your overall data usage, and even set a cutoff point afterwards which your phone will stop using mobile data altogether until your billing cycle resets.

You can find third-party programs that will perform some of those functions for both Android and iOS. If you're using a pre-Ice Cream Sandwich phone, try My Data Manager Free; if you're using an iPhone, look for DataMan Free. Both apps provide basic monitoring and alerting services for your mobile data usage.