If you want a founder to take your design work seriously, learn two numbers: CAC and LTV. They decide which design problems matter and which are decoration.
CAC is the total money spent on acquiring customers divided by the number of customers acquired. Simple formula, but one word does the heavy lifting: acquired. A signup is not an acquisition. A download is not an acquisition. A customer counts as acquired only when they have experienced the product's core value and shown the first signal of sticking around. By that definition, onboarding design directly changes CAC. That is leverage designers rarely realise they have.
LTV is what one customer is worth across their whole relationship with the product. A common way to estimate it: average order value multiplied by order frequency multiplied by how long they stay. Every variable in that formula is something design can move. Better recommendations raise order value. Habit loops raise frequency. A product people love raises the retention period.
A common benchmark is that LTV should be at least 3 times CAC. Below that, the business is buying customers at a loss. Well above it, there may be room to grow faster by spending more.
Here is what even experienced teams miss. A ratio of 1:7 sounds fantastic, but the ratio only tells you the eventual return. The payback period tells you when the money comes back. If it takes 18 months to recover CAC and the company has 12 months of runway, that beautiful ratio is a slow-motion crisis. Fast payback lets a company reinvest into the next batch of customers sooner, which is what makes a growth flywheel spin.
Because the highest-leverage way to improve both numbers is rarely more ad spend. It is better onboarding, better activation, and better retention, which are design problems. Designers who understand this stop being a cost on the marketing line and start being the people who fix it. This is the kind of thinking we drill at Nofolios on live company briefs.
