If you feel that your battery life is ok and there is no obvious experience, you don't necessarily need to replace it immediately, you can continue to use it. If you feel that your battery life has dropped significantly, and it is accompanied by changing your phone card, it is recommended to change a new battery to make the device rejuvenate and play better for several years.
If the iPhone uses the system from iOS 10.2. 1 to iOS 1 1.2.6, and the battery life is too low, go to Settings >; A notice "iPhone battery may need repair" may appear in "Battery".
If iPhone uses iOS 1 1.3 or higher, it can be set in->; Check the battery and performance of the iPhone in the battery to check the health of the battery. When the battery life is less than 80%, the battery life will be significantly reduced, and CPU frequency reduction may occur, which may lead to the phone being stuck.