It is always a good idea to take the regular backup of your Android device to avoid any mishap in which you may lose whole the data of your Android device. It may either happen with any conflicting app or due to factory reset which can wash you Android device to the factory default.
If you are planning to reset your Android device to the default factory reset, it is rather a must to take backup of your Android device so that after reset you may restore important data back to your Android device.
To set and activate backup and automatic backup may be done with a purpose to save your Google account password & other settings, data about apps downloaded and installed in your Android device, call data, messages, contacts, images, videos and many things like this.
To set / activate backup, you may get help from the instructions.
Instructions
Command Line: Settings – HOME > Backup & reset – PERSONAL > Backup my data.
1: Tap the icon of ‘Settings’ on the HOME screen of your Android 4.4.4 KitKat device to open up the ‘Settings’ screen. 
2: At the ‘Settings’ screen, scroll down to the PERSONAL section and tap the ‘Backup & reset’. 
3: At the ‘Backup & reset’ screen, see the ‘Backup my data’ is not checked, i.e. disabled. It means, the Android is, currently, not activated and enabled to take backup of the apps, Wi-Fi, passwords and other settings of your Android device. In addition to it, ‘Backup account’ and ‘Automatic restore’ are also disabled. 
4: Tap the ‘Backup my data’ to check and enable it. See with the activation of the backup my data, ‘Back up account’ and ‘Automatic restore’ is also enabled and activated.
5: See the ‘Automatic restore’ is check by default when the ‘Backup my data’ is activated. Android device will, now, restore settings and data, automatically, upon reinstalling apps. 
Now, feel free to install apps as the existing data of your Android device will be backed up and restored after installation of apps.
That’s all!