According to Apple, any iPhone with a battery capacity of 80% or above is considered to be in optimal condition. However, iPhones can run well with batteries as low as 80% performance in Maximum Capacity. If your iPhones battery health has slipped to 75% or below, it will still perform well, but you can expect further degradation and may see lower numbers and worse performance in the near future. If your iPhone battery health percentage drops below 80% within the duration of your warranty, which is usually about one year, then Apple will replace the battery. Its important to note that over time, the rechargeable batteries in all iPhone models will diminish in their capacity and peak performance and will eventually need to be replaced. To maximize battery performance and help extend battery lifespan, you can follow these tips:

• Keep iPhone half-charged when it’s stored for the long term.
• Avoid charging or leaving iPhone in hot environments, including direct sun exposure, for extended periods of time.

Its also important to note that obsessing over the health of your iPhones battery is not necessary. The "Battery Health" percentage in the settings menu is a feel-good number that doesnt really tell you anything meaningful about the actual health of your battery.