Although not necessary, this add-on is entirely up to you. Almost every model of Otterbox cases comes with a beveled edge, which protects the screen when laying it down on surfaces. However, if you drop the phone on a pointed rock, for example, the screen won’t be protected. In this case, it may be beneficial to get an add-on screen protector. Be sure to check and ensure the specific model of the case you own is compatible with screen protectors.