Retention analysis, often called survival analysis, is crucial for understanding and enhancing user retention alongside new-user acquisition metrics, ensuring that user growth translates into a sustainable and profitable customer base. While acquiring new users is initially exciting and prioritized, it is essential to analyze why customers continue to engage with a product, as neglecting this can lead to financial losses if acquisition costs surpass customer lifetime value (LTV). Product teams can leverage retention analysis to understand customer behaviors, segment users into cohorts, and compare retention rates to improve their strategies, such as determining how long different personas stick around, evaluating recent product changes, and measuring the impact of acquisition sources on retention. By defining meaningful retention goals, tracking in-app user behavior, and segmenting data by cohorts or acquisition sources, teams can identify key factors that influence retention and refine their approaches to boost user engagement and profitability. Additionally, measuring retention trends over time and analyzing engagement events provide insights into the quality of user retention, allowing product teams to focus on aspects that drive early user achievements and long-term customer loyalty.