Turn Down the Display & Keyboard Brightness 

Laptop displays are power-hungry, and MacBook panels — especially the brighter, HDR-capable ones — are no exception. If you tend to run your Mac at full brightness for purely aesthetic reasons, your battery will suffer the consequences.

Using max brightness indoors when you don’t actually need it is not necessary. Your eyes adjust to lower brightness, especially at home or in your office.

The same goes for your keyboard backlight, which not only doesn’t need to be cranked up when you’re watching a video, but can actually be a distraction.

Reducing your brightness on your MacBook is pretty easy. For the display, simply press the F1 key to reduce the brightness one notch at a time until it reaches a comfortable level. If your keyboard has the icon, pressing F5 will do the same for the keyboard backlight. Alternatively, you can go to System Settings > Displays or Keyboard and drag the appropriate brightness sliders to the left.