11. Battery Saver

Your phone is dying and you don’t have your phone charger? Don’t worry you have hidden battery saver in your phone. Go to the settings >> General >> Accessibility >> And turn on Gray Scale mode. It will save your battery life and will not let it die soon. Also with the new iPhone 6S and 6S Plus and the new update of iOS 9, there is actually a new option to put the phone in battery saver mode.