It’s common for a team to look at CAC (customer acquisition cost) as if it were the only metric that mattered. The problem is a low CAC doesn’t mean anything good if the customer you acquired isn’t worth much over time.
LTV without CAC is an illusion, CAC without LTV is short-sighted
LTV (lifetime value) tells you how much a customer is worth over the life of their relationship with your business. CAC tells you how much you paid to acquire them. Neither one, alone, tells you whether your growth is healthy. It’s the relationship between the two (LTV:CAC) that actually matters.
A simple reference point
A 3:1 ratio (LTV three times CAC) is often considered healthy across many business models: it means you’re generating enough value to justify the acquisition investment, with room to reinvest in growth. A ratio of 1:1 or lower is a warning sign — you’re spending almost as much as you generate, and any cost fluctuation can push you into a loss.
The mistake of optimizing CAC in a vacuum
Aggressively lowering CAC without checking what happens to the LTV of the customers that cheaper channel brings in can backfire: if those customers retain worse or spend less, you lowered the cost but also lowered the value — the business didn’t improve, it just changed shape.
How this translates into concrete decisions
When you evaluate a new channel or campaign, don’t judge it only by cost per acquisition. Look at what happens with those users at 30, 60, and 90 days: do they retain the same as the rest of your base? Do they spend more or less? That’s the question that actually determines whether that channel deserves more budget or less.
If you need to build the LTV and CAC measurement framework for your business, message me on WhatsApp and we’ll build it together.