Your Screen Is Always Bright
Auto-brightness has been an option for iPhones for a long time and is automatically enabled when you buy an iPhone. However, most users have been in a situation where they need to manually make the screen brighter to see something on the screen more clearly. The screen may look great, but it’s draining your battery life.
Make sure that automatic brightness levels are turned on so that the screen will darken and lighten again naturally when needed. On newer iPhones, you’ll want to enable True Tone in Settings > Display & Brightness to achieve this effect.