Is it normal that my smartphone's battery runs out by the end of the day?

Yes its normal. You may need to reset your phone and change some of the default settings if you want the battery to last longer. 

Most phone settings enable them the do the fantastic things we like. We also often download additional apps that drain battery. 

Background apps tend to drain batteries as they try to connect to a network but can’t because of poor or lack of signal. You may notice your phone getting hot. You’ll need to turn some of these apps off. You also need to consider the state of your battery because older batteries tend to drain faster and require more frequent recharge.

How to make your battery last longer

Here are some detailed stuff you can do to preserve your battery or keep your phone on for longer
1) If you are a heavy phone user, your phone will drain much quicker than normal. You'll need to get a power bank. 

2) Check how frequently your phone syncs emails and other apps. For example, if not necessary, consider syncing emails 2-3 times daily rather than 3-4 times.

3) Check your background apps. Have a look at this blog for some ideas and step-by-step hints - Phone-battery-runs-down-quickly-do-I-need-a-power-bank?

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