Activation rate

You choose that moment. For an invoicing tool it might be sending a first invoice. If 100 people sign up and 25 send an invoice in their first week, your activation rate is 25%. People who never activate rarely pay.

At your stage, a better activation rate is often worth more than more signups. Watch 10 new users try the product, find the step where they stop, and fix your onboarding. This lifts your free trial results and lowers churn. Then improve activationsoon one step at a time.