All iPhones are powered by lithium-ion batteries, which deteriorate a little bit every time they're recharged, and the more often you recharge an iPhone's battery to 100%, the quicker its lifespan reduces. Though researchers are working on the development of next-generation battery tech, lithium-ion remains the best option for smartphones right now.

Apple provides a few ways to keep tabs on your battery health so you can make usage changes as needed. Under Settings > Battery > Battery Health, you can see your iPhone battery's charge capacity, and the Peak Performance Capability report is a one-liner that reveals whether your iPhone is operating at normal levels or if its performance is impacted by poor battery health.

Apple also has a feature called Optimized Charging that minimizes the amount of time your iPhone is fully charged, and helps delay the aging of its battery; when the feature is turned on, your iPhone will slow its charging after 80%. The iPhone learns how often you charge it, and when it anticipates you'll have your phone plugged in for a while, it turns on Optimized Battery Charging.