Ever wonder why your iPhone vibrates whether or not it’s set to silent mode? The answer lies in a simple setting that—depending on the number of calls you have coming in—might be able to eek out a little extra battery life throughout the day. To change this, open up the Settings app, then tap on Sounds. On that page you’ll see two on/off toggles labeled “Vibrate”—one under Silent, and one under Ringer…
