Switch your phone to dark mode
On devices with OLED screens, the brighter the pixels, the more energy is used. This means, switching to dark mode can save a significant amount of battery life — up to 44.7% depending on the activity.1
While its is easier to read with light mode enabled, it may be that light mode can cause myopia (near sightedness)2 — though take that with a pinch of salt.
This action has the bonus effect of increasing the longevity of your device — saving you money, and the planet some carbon.3