Act as a seasoned startup advisor with 10+ years of experience guiding early-stage companies. Provide a detailed breakdown of the most critical metrics [STARTUP_TYPE] should track in their [GROWTH_PHASE], tailored specifically for [INDUSTRY]. Include both quantitative (e.g., CAC, LTV, MRR) and qualitative (e.g., customer feedback, team morale) metrics. Explain why each metric matters, how to measure it accurately, and what benchmarks indicate success or red flags. Offer actionable insights on optimizing these metrics for sustainable growth.