Once product-market fit is achieved, the singular obsession must be retention. Before focusing on expansion metrics like NRR or efficient acquisition (CAC), you must first prove you can stop the "leaky bucket" and keep the customers you've already won.

Waiting a year to measure retention is too slow. Create a leading indicator by defining an event (E) that a percentage (P) of new customers must complete in a specific time (T) to predict long-term success (e.g., 80% of users use 5+ features in month one).

Many founders mistakenly define Product-Market Fit by revenue (e.g., "$1M ARR"). The correct measure is the ability to predictably create customer value. This is best quantified by a leading indicator for long-term retention, not sales figures, as revenue can be achieved without true market fit.

In hyper-growth AI companies with annual contracts, renewal data is a lagging indicator. VCs scrutinize user engagement as the most critical leading indicator of future retention, as a large part of the customer base has not yet faced a renewal cycle.

Metrics like product utilization, ROI, or customer happiness (NPS) are often correlated with retention but don't cause it. Focusing on these proxies wastes energy. Instead, identify the one specific event (e.g., a team sending 2,000 Slack messages) that causally leads to non-churn.

The true indicator of Product-Market Fit isn't how fast you can sign up new users, but how effectively you can retain them. High growth with high churn is a false signal that leads to a plateau, not compounding growth.

Revenue or customer numbers merely indicate sales ability. True product-market fit is proven when customers derive enough value to continue using the product, making retention the most accurate lagging indicator of value delivery.

Founders mistakenly define product-market fit by revenue or customer numbers. A better definition is achieving a high retention rate, proving customers get long-term value. This prevents scaling a business that can't retain its customers.

Your leading indicator for retention isn't a vague metric like NPS. It's a specific, binary event or milestone within the product. After a customer achieves it, their context changes so much that churning would feel illogical. Identify this event and get 95% of new users there within one month.