Drop CAC and LTV. Look at payback period.

Almost every first meeting with an investor in SaaS lands on the same conversation: “What’s your CAC? What’s your LTV?” Both metrics are useful in mature companies and almost useless in early-stage ones.

what each one is

• CAC (Customer Acquisition Cost). What you spent on marketing and sales divided by how many new customers you brought in. The problem is that it floats in a vacuum — it doesn’t mean anything without something to compare it to.

• LTV (Lifetime Value). What an average customer will leave with you over their lifetime. In early stage you’re guessing. You don’t have the historical record to extrapolate. Any number you plug in is the founder marketing themselves to the investor.

• Payback period. CAC divided by the monthly revenue (or monthly margin) of one customer. How many months it takes that customer to pay back what they cost to acquire.

why payback period wins

It’s observable (not projected), simple (one number), and actionable (it tells you to slow down, hold steady, or accelerate).

Three ranges guide the strategy:

• Under 6 months. You’re being conservative. You should probably accelerate spending on acquisition — the flywheel will get better on its own.
• Between 6 and 12 months. Healthy equilibrium for sustained scaling. Most successful B2B SaaS lives here.
• Over 12 months. Red flag. Either there’s a churn problem, or you’re paying too much for acquisition, or both.

the detail people forget

As you scale, payback period gets worse, naturally. The first customers are the easiest. The next ones are progressively more expensive. It’s not a sign that something broke — it’s the predictable cost of growth. What matters is that it doesn’t run away.

conclusion

Drop the CAC/LTV noise. Look at payback period. It’s an honest metric you can’t fake on a deck.

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