There are things you can do to help minimize battery drain (and lower data usage) in addition to apps.
Double click on the home button and a screen will appear with open apps. Flick them off the screen to close them. (The latest update to the One M7 has a button on that screen to close them all at once.)
Put the phone in the Power Saver Mode
Activate the Sleep Mode (under Battery Manager) to turn off data during long periods of inactivity.
Go to your Google Play Store and turn off auto updating of apps, update apps manually only when in WiFi.
Get rid of any redundant apps; those that might have been made obsolete by software updates.
Stop apps from constantly refreshing, change settings to only refresh when used. (Weather, news, etc.)
Minimize notifications (weather alerts, etc.)
Keep your GPS off until it is needed for an app like Waze or Maps (put a GPS widget on the screen for easy on/off)
Turn WiFi off when you know you won't be near wifi for a long time.
Of course, the screen is probably the biggest battery drainer, minimize brightness to an acceptable level.
Consider wearing a watch so you're not turning the phone on just to look at the time.
Any other ideas, anyone?
HTH