What’s really going on inside your Android device? When do you use data and what apps consume the most? Many carriers now place limits on data plans that require you to pay fees per download if you go over a monthly allotment. With a usage monitor app like Onavo, you can track your data usage and save yourself overage charges.

The setup feels easy. When you first launch the app it asks you a few quick questions about what your data limit is, what day of the month the counting starts and ends for your service plan, and what apps you want to monitor – all apps or a few selected ones. From there, Onavo will watch and learn in the background. Whenever you want, you can check your usage profile and the estimates (based on your current levels), and see whether or not you will go over your data plan limit in the current month. The app section will break down which apps consume the most data showing average weekly use. All sections present helpful bar graphs for visual thinkers.

The app features an aptly-titled Data Plan Advisor that will tell you to shop for a different data plan – with either a higher or lower data limit – based on your usage, if your current plan isn’t the right fit. A detailed settings screen also lets you tailor alerts to warn you of approaching limits.

All in all, the app proves itself useful for anyone using an Android device under a data limit-based service plan. Try it out for yourself.