https://www.apple.com/batteries/maximizing-performance/

“Battery life” is the amount of time your device runs before it needs to be recharged.
“Battery lifespan” is the amount of time your battery lasts until it needs to be replaced. Maximize both and you’ll get the most out of your Apple devices, no matter which ones you own.

There are two simple ways you can preserve battery life — no matter how you use your device:
adjust your screen brightness
and use Wi‑Fi.