"Unraveling the Mystery: The Decline of iPhone Battery Longevity"
The gradual decrease in an iPhone's battery life from 100% to 99% is a normal part of battery wear and is not a cause for concern. Every charge/discharge cycle wears the battery a little, and after around 500 complete charge cycles, the battery is designed to retain up to 80% of its original capacity. The more you use your phone, the more it wears the battery. Additionally, the battery's actual capacity is slightly higher than what Apple claims, which allows it to stay at 100% for longer when the battery is new. However, there are steps you can take to reduce additional wear, such as using a good-quality charger, keeping the phone at room temperature, not leaving it on the charger all the time, and keeping the phone updated with iOS updates. Signs of a dying battery include rapid discharging, crashing under load, failure to charge to 100%, and physical damage.