The customer acquisition cost (CAC) must be lower than the revenue generated from a user to ensure sustainable growth.

For paid growth, ensure you have revenue before investing in ads, and understand your customer acquisition cost (CAC) versus the lifetime value (LTV) of your users to ensure profitability.

It's a common mistake to assume that paid acquisition costs will remain constant; in reality, it often becomes more expensive to find and convert users over time.

For acquisition metrics, track signups per week and differentiate between organic users and those invited by others to understand growth better.

Track the number of paying customers to measure growth; increasing customer acquisition rates can demonstrate to investors how quickly you're scaling.

Acquiring better users is essential; targeting the right customer can significantly improve your cohort retention rates.

Paid growth involves spending money to acquire users. It's important to ensure that the lifetime value of a customer exceeds the cost of acquiring them, or else the growth strategy may not be sustainable.

If your startup has strong network effects, focusing on active users may be more important initially, with revenue becoming a focus later on. It's crucial to define what 'users' means for your startup, as it can vary significantly. For example, having 100 users could mean they just signed up or that they actively engage with your product daily for about 10 minutes. The latter is a much more valuable metric.

Tracking customer retention is essential; it helps you understand how many users continue to engage with your product over time, which is a key indicator of success.