How to make your iPhone or Android device vibrate when getting a call

While most feature phones in the past had their vibrator motor set to do its thing whenever a call came through by default, quite a few modern smartphones require that you dig through the Settings menu and hunt down the option to enable this feature. It's handy too, especially if you keep your phone in your pockets, and for when somebody or something around you is going berserk and you can't hear a thing. So turning vibrations on for calls ensures that the odds of you missing that next important call are minimized.