As I posted in Motorola Droid Razr: First steps the first thing I noticed was that my phone leaked data. In that case, the culprit was a YouTube app which I eventually found out how to disable (Motorola Razr: Setup contacts (and the youtube problem).
A lot of people get smartphones and are unaware that the cute apps and synch functions all tear through data, or add to your account (or dissolve your airtime). Visit the post The desire is greater than the capacity for The OH's (insightful) thoughts on this and some equally insightful comments.
Back to my problem...
My new contract comes with 250mb, but this only becomes active the 1st July so I immediately did the *111# thing to buy a data bundle (actually to convert airtime to a data bundle). This way I am paying only 90c/Mb instead of the R2/Mb out-of-bundle rate.
That sorted it was time to plug the leaks. A feature called Data Manager is part of the Razr software. It has options for battery savings by reducing data traffic when not needed (see Motorola Razr: Saving the battery). Not surprisingly it also helps you control data leaks(duh). Tap to Menu>setting>Data manager where the data meter shows usage. Tap the readout and you get a bar graph by days, and tapping Show usage by activity brings up a pie chart that show the main culprits.
Tap Data saving to get the screen where you can turn the data saver on and off. What this does is pause certain download functions till a WiFi connection is available. There does not seem to be a way to customise this further.
What you have to figure, is that whenever the phone tries to synch across the Internet then it will eat data. That was the problem with the YouTube app I had on the menu screen, by default, at startup. It wanted to synch a list of the latest YouTube videos, something I'm not interested in. Removing the app from the Menu sorted that. I imagine as well that at startup, when a lot of things want to synch, it will eat data. Also every time you set up an app that connects across the internet for the first time, it will eat data. Probably further synching will use less (depending on if the app retrieves just changes or the whole damn page). AFAIK Facebook is a culprit here as it retrieves the entire frame and not just the updates. Obviousy stuff like Twitter, Facebook, Gmail, Weather, GPS, Maps, Location finder etc. that have to constantly update will eat data. So turn off what you don't use and monitor the rest (with the Data manager) till you know what's doing.
A feature that both annoys and delights is the Consent window that pops up a warning on some apps. Like the UAC in Windows, it requires action from the user to turn on an app on that uses data or battery. Unfortunately there is usually no other customisation except on or off and the dialogue doesn't give specific informations except that the app or setting may (or may not) use battery or data.
As I said in Saving the battery, turning off some things saves the battery and stops them trying to synch. The GPS goes off with a toggle shortcut or Menu>Settings>Location and security, as does the Locator. Wireless goes off at Menu>Settings>Wireless & networks (or a toggle) as does Bluetooth. Removing apps from the Menu screen also works for some - like YouTube
Well thats about as far as I've explored. I imagine you can set up Smart action rules that will turn off certain functions. Background synch can chew data, but it can be set to turn off when the phone is in sleep mode. That means it only works when you are actually using the phone, but surely it then just synchs what it missed while it was sleeping? Turning it off does save battery, but not sure about data.
I found settings under Menu>Settings>Accounts>gMail that allow me to turn off certain gMail synch functions like the contacts and calender, so there is bound to be more. Under Apps>Email for instance, I can change how often mail is retrieved. This as been a standard feature on all WAP enable phones for ages, but in this case setting it properly means battery and data saved.
I have not set up all the social media functions etc - yet, but with Gmail and email I am using about 1Mb a day. Lets see how that goes.
The adventure continues