Proper charging of your phone is the main condition for its stable operation for many years. Unfortunately, not all users follow all the rules for safely recharging the device. 
The first and, perhaps, the main rule is to use only original devices for charging. If a wire or adapter is out of order, it's best to spend a little more money buying a new one from an official store. Otherwise, you may have to pay a lot more to repair the device after a while.
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The second rule is to monitor your surroundings. Do not leave your phone charging in a room with a window open during the cold season or in direct sunlight. The presence of water nearby is unacceptable.
The third point is to try to charge the device fully. If you often recharge the device not up to 100% percent, the battery capacity will not be displayed correctly and you will have to either calibrate or replace it.
Do not connect your phone to power sources that are too powerful, because this will also harm the battery.
The rules are extremely simple and every user can follow them.