It's OK to admit that picking a cellular plan makes you nervous. There are a lot of angles to consider, and you don't want to get it wrong.

Pick a plan that's too small and you'll go over your limit and rack up unwanted charges – or run into speed throttling on an unlimited plan. Go too large and you'll be wasting money on data you don't use – and who likes to waste money?

I've talked before about the common mistakes many mobile customers make when choosing a mobile data plan and how to avoid them so you get the perfect plan for you. But even if you pick a data plan that seems just right, you can still run into trouble.

You might install an app or turn on a feature that uses up your data faster than you realize. If you aren't careful, your data can be gone before you know it.

Don't let data overages take you by surprise. Download this data monitor app so you can see how much data you're using and which apps are responsible.

I'm going to tell you about some of the big culprit apps and how to stop them. You might be surprised how much data you save – you might even be able to downgrade to a cheaper plan.

1. Free texting apps

Depending on the kind of information you're sending and receiving, free texts might be costing you more than you think. It doesn't matter if you use Apple's iMessage, Google Voice or a variety of third-party apps like TextFree, textPlus or WhatsApp; they all use your cellular data.

If you're just sending text-based messages, then there's really no problem. Those are so tiny, they don't even budge the needle.

But when you start sending or receiving photo or audio messages using cellular, you're going to use a lot more data. If you do anything with video messages, you'll be burning up data like crazy.

Luckily, most phone messaging apps download larger content like video and audio files only if you select them. Make sure to play these messages only when you're connected to a Wi-Fi network and you won't be using any of your cellular data.

2. Videos on Facebook

If you've fired up the Facebook app recently, you've probably noticed it handles videos a little differently. When you scroll past any video in your news feed, it immediately starts playing.

Of course, that's using up your data plan, so thank you, Facebook. Fortunately, you can put a stop to it.

(It isn't just Facebook, by the way. Twitter is rolling out video ads soon. So far, it sounds like they won't auto-play, but watching them will still burn data.)

In Android, open the Facebook app and go to Settings. Change "Videos Auto-play" to "Off." You can also set it to "Wi-Fi only," so they auto-play only when you're connected to Wi-Fi, but I prefer to control when videos start.

For iOS, go to Settings>>Facebook and tap Settings. Under "Video," tap Auto-play. You can choose "Off" or set it to "Wi-Fi only."

If auto-playing videos have pushed your data use into expensive territory, contact your provider and explain the problem. It might be willing to give you a break on overage fees.

Uploading video or photos to Facebook from your phone will burn just as much data – sometimes more – than viewing it. Always wait until you're on Wi-Fi before uploading media.

Can't wait until you get home or back to the hotel? Click here to find free Wi-Fi hotspots near you.

3. Streaming music

Streaming music services are a great way to listen to all the music you want without spending a fortune. Click here to learn more about popular streaming music services.

Even better, most services have free apps so you can listen on your smartphone or tablet. If you've read this far, though, you know there's a catch.

Streaming music apps, free or not, are definitely something to be careful with if you're on a limited plan. Apps like Spotify use around 0.72 megabytes per minute, and you can expect around the same amount for Pandora and similar apps.

On a 2GB data plan, that gives you less than 40 hours of music listening a month. That's only if you don't use data for anything else.

Again, the best solution is to stream music almost exclusively over Wi-Fi when you're at home or work. That way, streaming it over cellular a few hours here and there won't be such a big deal.

If you're really burning through your data plan but don't want to upgrade, try grabbing an app that compresses your data so you use less overall. Onavo Extend, for example, is a free app that can give you the equivalent of up to five times more data. I like the sound of that.

On the Kim Komando Show, the nation's largest weekend radio talk show, Kim takes calls and dispenses advice on today's digital lifestyle, from smartphones and tablets to online privacy and data hacks. For her daily tips, newsletters and more, visit her website at http://www.komando.com.