How long your battery will last varies depending on many factors including how you use the device, Mobile Network signal strength and device usage periods. Also, having many apps running in the background will consume additional power. Close apps to reduce the power consumption.
Your device will also consume more power when you use mobile data in areas with very low Network signal.
The battery is a consumable item.
Overtime, eventually, its ability to hold charge will reduce. If over time you find that after optimising your device (see below note) the battery appears to hold much less charge than it used to, it may be time to replace the battery. To maximise your battery life time:
ㆍ Optimise device performance by going to Settings > Device maintenance
ㆍ Set apps to sleep to extend your battery life by going to Settings > Device maintenance > Battery
ㆍ Turn off the display when you aren't using the device.
ㆍ Turn off Bluetooth, Wi-Fi, and GPS when they are not in use.
ㆍ Apps that automatically sync data in the background will consume more power, so turning off auto sync will help.
ㆍ Set the screen timeout to 30 seconds and the display brightness to Auto.