Does it help battery life if I only charge to 80 percent each time instead of 100 percent?

Hello,

A quick Google search gave me this:

”Benefits of Optimized Battery Charging

Research has shown that leaving your phone between 30-80% helps you get the best out of your phone's power back-up, most especially Lithium-Ion batteries. Constantly charging your iPhone to 100% will degrade the battery over time and reduce its lifespan faster.” - iPhoneGeeks.com

Also, you can checkout these links:

About Optimized Battery Charging on your iPhone - Apple Support

Batteries - Maximizing Performance - Apple

When to Charge Your iPhone or iPad - Apple Community

Sincerely,

Captain

The short answer is No. The absolute best way to get maximum use on a charge, as well as slow the decline of battery capacity long term is to enable Optimized Battery Charging (Settings/Battery/Battery Health) and charge the device overnight, every night. The battery will fast charge to 80%, then pause. During the nighttime pause the phone will use mains power instead of battery power, allowing the battery to “rest”, and thus reducing the need to charge the battery quite as often. The phone will resume charging to reach 100% when you are ready to use your phone; it will “learn” your usage pattern. If you enable iCloud Backup (Settings/[your name]/iCloud - iCloud Backup) the phone will back up overnight also, assuring that you can never lose more than the current day’s updates.

Here’s the long answer→When to charge your iPhone or iPad | Communities, (which -Captain- has already linked to)