A new study says that smartphone users are overpaying for their service by several hundred dollars each and every year. The study, put together by Billmonitor, notes that people are overspending primarily because they’re on contracts that wildly overshoot their needs. People have a habit of signing up for contracts with far more voice minutes than they use, and it’s primarily for this reason that smartphone users are paying much more than they need to. In other words, double-check your statement to make sure you’re on the right contract.

But it’s not only that smartphone users are paying for more voice minutes than they use. Now that data-heavy services (the usual suspects like Spotify, etc.) are commonplace, smartphone users often go over their monthly data limit. Pass the limit, per per megabyte. It’s a cruel world. The study found that the average smartphone user eats up some 133MB of data per month. That, of course, will only increase as users discover and use more data-heavy apps like the MLB app.

The study also says that people are afraid of “bill shock” (freaking out at the unexpectedly high cost of your monthly bill), hence their tendency to overshoot their contract requirements.