HTC One: Extend battery life - the best tips

Preparation is everything - how to set up HTC One to save battery power:

After unpacking, "train" the battery: In order to utilize the maximum capacity right from the start, you should always charge the One in full cycles during the first week, ie fully charge it from 0-10% remaining battery to 100%. Later on, you should also run through such complete cycles from time to time - this will keep your battery fit longer.
Deactivating unnecessary apps: You certainly don't need all the preinstalled apps - they will still gnaw at the power. Many cannot be uninstalled, but you can at least deactivate them in the settings under »Apps«. If, for example, you are not logged in to Google+, you can shut down this app right away.
Power guzzlers HTC Sense: Elaborate widgets such as HTC's exclusive "Blinkfeed" on the home screen suck heavily on the battery. If you want to continue using it, set exactly how often and how many notifications and news you want to receive here. The less and less often, the less the widget wakes up your HTC One and lets the processor and data connection work.

Regulate display brightness: The biggest power guzzler remains the display. You can save a lot of battery if you tweak the brightness here, precisely because the HTC One's auto brightness is often a bit too bright. Change to manual settings here and dim as much as possible.
Check connections: Switch off the battery eaters such as GPS, Bluetooth or WLAN when they are not needed. Use WiFi as often as possible instead of the mobile data connection via 3G or LTE, because HTC One in particular has a particularly energy-saving WiFi module.
Use energy saving mode: Under »Settings« and »Power« you will find a power saving function that you can even personalize. Here you can limit the processor performance, for example, which does not noticeably reduce everyday performance thanks to sufficient performance reserves. You can also set the display brightness and vibration here. Be careful when influencing the data connection: Under certain circumstances, you may no longer get emails and Whatsapp messages, for example. Here, staying up-to-date is competing with battery savings - you decide!

Professional task manager "Greenify": Although this small, fine free app from the Play Store requires root rights, it is all the more effective for that. It manages the background processes and reliably prevents apps from running unnecessarily in the background and consuming electricity. Mark apps once and the app will do the rest on its own - quietly and effectively.
This tip explains how to root HTC One.