What metrics should I track for my startup?

Focus on metrics that drive decisions, not vanity metrics that feel good. For SaaS: MRR, churn rate, CAC, LTV, and LTV:CAC ratio. For marketplaces: GMV, take rate, and liquidity. For all businesses: revenue, growth rate, and unit economics. Track weekly, review trends, and be honest about what the numbers mean. One key metric should be your North Star—the single number that best indicates if you're winning.