It is normal for Apple's mobile phone battery to drop to 97 for half a year. Under normal circumstances, the loss of lithium batteries is inevitable. It is normal for users to use it for half a year, and the healthy surplus is between 85% and 99%, generally around 95%. If it is 100% or less than 80%, it is not normal.
Apple batteries 98 to 97 are about 1 month. Apple uses a lithium battery, and the number of cycles is about 500 times. After more than 500 times, the battery will drop significantly. In other words, when the health of the Apple battery reaches 80%, the battery can be replaced.