The app market is growing rapidly with revenues approaching $80 billion and mobile users surpassing desktop users since 2015. A smooth and reliable mobile experience is crucial for user retention, which is more important than the number of features or update speed. Good quality can lead to positive reviews, higher revenues, and word-of-mouth recommendations. To increase app quality, it's essential to listen to users, test apps thoroughly before release, and engage with dissatisfied customers to turn them into positive reviewers. By focusing on user retention, developers can achieve higher revenues and ROI by keeping existing customers happy and engaged.