An anonymous reader writes: I've carried a smart phone for several years, but for much of that time it's been (and I suspect this is true for anyone for whom money is an object) kept pretty dumb — at least for anything more data-intensive than Twitter and the occasional map checking. I've been using more of the smart features lately (Google Drive and Keep are seductive.) Since the data package can be expensive, though, and even though data is cheaper than it used to be, that means I don't check Facebook often, or upload pictures to friends by email, unless I'm in Wi-Fi zone (like home, or a coffee shop, etc). Even so, it seems I'm using more data than I realized, and I'd like to keep it under the 2GB allotment I'm paying for. I used to think half a gig was generous, but now I'm getting close to that 2GB I've paid for, most months.
This makes me a little paranoid, which leads to my first question: How accurate are carriers' own internal tools for measuring use, and do you recommend any third-party apps for keeping track of data use? Ideally, I'd like a detailed breakdown by app, over time: I don't think I'm at risk for data-stealing malware on my phone (the apps I use are either built-in, or plain-vanilla ones from Google's store, like Instagram, Twitter's official client, etc.), but of course really well-crafted malware would be tough to guard against or to spot. And even if they can be defeated, more and more sites (Facebook, for one) now play video just because I've rolled over a thumbnail. Read on for second part of the question.