First of all, you use an Apple mobile phone. As we all know, the battery of the Apple mobile phone itself is not as resistant to electricity as the domestic mobile phone battery.
And you found that the mobile phone battery has not been used for a long time at first, which is correct. The current batteries are all lithium batteries, which will definitely change after repeated charging and discharging for a long time. Therefore, the personal charging method is very important.
First of all, it's best to remind you to charge when the battery is too low.
The second best thing is to turn it off and charge it.
To sum up, this can effectively protect the optimality of mobile phone batteries, and will also be used for a long time.
I hope my answer can help you and be adopted.