A few months ago, AT&T was the first mobile carrier to switch to tiered data usage plans, and now the other big behemoth, Verizon, is following suit. AT&T charges $15/month for 200MB of data, or $25 for 2GB (if you were an original iPhone user they grandfathered in the $30/month for unlimited data). We tracked our data usage for several months and the $15/month plan looked good for both of us (we did have to upgrade to unlimited texting: they charge $5/month for 200 text messages and both of us went over that) so we said goodbye to unlimited data to save some money.And how did that go, you ask? Well….

Fast forward the two months since, and I have consistently been pushing the ceiling on my 200MB limit. What gives? I keep Push and Notifications turned off and I don’t spend THAT much time on my iPhone (or do I?). There’s no precise way to track which apps are the hogs, but this site gives me some solid clues (Android phones have the same problem – don’t feel special!). Biggest offenders: Facebook, Google Maps, Pandora (and associated streaming symbols for facebook” title=”music symbols for facebook”>music apps like KCRW) and iTunes and the App Store. While I never download songs on iTunes I do download apps via the App Store. I also use Google Maps a lot, and do post updates to Facebook. But hey, what do you really do a lot on a smartphone? Duh! You browse the web and coincidentally another data hog is Safari! Oh, and there’s also the Flickr app – ouch! And did you just check the weather in Paris on the weather app? Snap!

So basically the lesson learned: you may think you’re going to save money by going cheap on your data plan, but be sure to keep an eye on your usage. Getting stung with overage costs will negate your savings fast! If you’re an AT&T customer, you can download the free myWireless Mobile app (and watch your data usage spike again as you download the app). We just upgraded my account to 2GB for $25/month as it is clear I have a problem sticking to 200MB/month (thanks a lot, Facebook and KCRW!).

What’s your data usage like? Do you know?