What used to be a simple way to make things louder or quieter has quietly evolved into a powerful control system built into every modern smartphone. With a quick press, you can take sharper photos, start recording a video in an instant, or manage music without even looking at your screen. During busy moments—rushing for a train, running on a treadmill, juggling groceries—those physical buttons become the most reliable, fastest way to interact with your phone.

But their impact goes beyond convenience. On many Android phones and iPhones, specific combinations of volume and power buttons can silently call emergency services, share your location, or trigger an SOS alert when you can’t speak or unlock your device. Paired with customization and automation tools, those same buttons can launch a flashlight, open the camera, or start a favorite app on command. The more manufacturers lean into this design, the clearer it becomes: the humble volume rocker has turned into one of the smartest, most important controls you carry every day.