How can I disable unwanted data usage?

I would like to remove unnecessary data usage. I have wifi at home and at work and I would like Android to synchronize/update apps/... only on wifi. In fact, I don't want Android to do any background action which consumes data when I'm not connected to a wifi network.

To sum up, basically, I would like a way (an app?) which disables data when not on wifi and enables it automatically when on wifi.

How can I achieve this?

I'm using Android 4.4 on a Galaxy Nexus (with the help of CyanogenMod 11).

Answer

There is one more standard Android setting, i.e. no app needed, which you can change - in fact anyone without unlimited cellular data should do this at first set up. As I can only check Android 5, I can't say how this is done in earlier versions:

1. 
   

   Open the Play Store App

   
   



2. 
   

   Go to Settings:

   
   
   
   
   • Click the 3 horizontal bars at top on left of search box.
   
   
   • Left panel slides out...
   
   
   • Scroll down and tap "Settings".
   
   
   
   


3. 
   

   First section "General", tap first item "Auto-update apps"

   
   
   


4. 
   

   Select third option "Auto-update apps over Wi-Fi only".

   
   

This disables a LARGE amount of the automatic data usage while apps auto-update whenever you're on Wi-Fi.

---

One warning about Restrict Background Data:

On the Settings->Data Usage page, you can scroll down and select each app and choose to restrict background data for that app. This will only allow background data on Wi-Fi for that app.

However, if you then use the Settings->DataUsage->more options->Restrict Background Data, this applies to ALL apps. If you then choose to allow it again, it resets ALL the Apps you've individually restricted back to no restriction. So if you're wanting that level of control, you will need to use a 3rd party app as suggested.

(Here's hoping that a future release of Android sets these as checkboxes on a list of ALL apps as it has for "Move to SD card" to make it easier to stop background data usage by unimportant apps off-Wi-Fi. Then it would be easy for a master control to restrict all apps not already restricted so that it wouldn't reset the checked items.)