There's no silver bullet for quitting nail biting. You have to work at it, and really commit to stopping. That being said, this app does a good job at showing you that you are actually progressing, and you will soon see results. It's an assistant for the mental commitment, and little else. The one major downside is that the little motivational pieces are often grammatically incorrect - seriously irritating. A better app would have the ability to track your own progress with pictures, showing you where you were and where you're going. Overall, it might help you, but it's ultimately all on you to stop. Even with the app, it's still pretty hard.