Android phones slow down over time. These steps restore snappiness without rooting.

Clear App Cache

Settings > Storage > Cached data, or per-app under Apps.

Reduce Animations

Developer options > Window/Transition/Animator scale to 0.5x or off.

Disable Unused Apps

Disable pre-installed apps you cannot uninstall.

Lite Apps

Use Facebook Lite, Messenger Lite, and Go edition apps on lower-end devices.