Analytics lets you make decisions based on data rather than guesses. Firebase Analytics is free and powerful: funnel analysis, audience segmentation, A/B testing. Mixpanel offers deeper analysis for event-based tracking.
Key metrics to monitor: DAU/MAU (daily/monthly active users), Retention, Session length, Conversion rate, and Churn rate. There's no need to track everything — choose only the metrics tied to business goals.
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