Vanity metrics are comfortable because they always go up. The metrics that matter are harder — and far more honest about the health of your business.

1. Cost per acquisition (CAC)

What it costs to win one paying customer. If this keeps rising, growth is not sustainable.

2. Return on ad spend (ROAS)

Revenue earned for every pound spent on ads. The single fastest signal of whether a campaign works.

3. Customer lifetime value (LTV)

How much a customer is worth over time. High LTV lets you spend more to acquire and still win.

4. Conversion rate

The percentage of visitors who take the action you want. Small improvements here compound massively.

5. Retention

Keeping a customer is cheaper than finding a new one. Retention is where quiet, durable growth lives.

Track these five and you will make sharper decisions than 90% of your competitors.