CPL is not enough because it only tells you what you pay for a submitted form. It does not tell you whether that person ever buys, how much they buy or whether they come back. So alongside CPL we measure the share of qualified (premium) leads, conversion to customer and the ratio between customer lifetime value and acquisition cost (LTV:CAC).
When a client first shows us the report for their Meta or Google campaigns, CPL is usually the first number. "We get leads at €6, that's great, right?" It depends on what happens to them next. The basics are in the article What is CPL?.
Why is one number not enough?
CPL measures one step: the form submission. In B2B sales, especially in the premium segment, leads are not equal. Most are not a fit for the product. A minority are. That minority often decides whether advertising is profitable.
What is a premium lead?
We set the criteria for each client before the campaign goes live. Typically they include:
- Decision-maker: a director, owner or marketing manager with a budget contacts us.
- Business size: the company meets a minimum threshold, which depends on the service.
- Timeframe: they are actively looking for a solution in the next 30–60 days.
- Geography: a market in the CEE region that we can serve.
A lead that does not meet these criteria is not worthless, but it matters less than a premium lead. Premium leads most often become customers with a high order value and a low churn rate.
What does the difference look like in numbers?
Compare two hypothetical campaigns with the same monthly budget of €400:
| Metric | Campaign A | Campaign B |
|---|---|---|
| Total leads | 80 | 10 |
| CPL | €5 | €40 |
| Share of premium leads | 5% | 80% |
| Premium leads | 4 | 8 |
| Premium lead to customer conversion | 25% | 40% |
| New customers | 1 | 3.2 |
| Average order value | €1,500 | €1,500 |
| Revenue | €1,500 | €4,800 |
Campaign A has a CPL 8 times lower, yet campaign B brings 3.2 times more revenue. The example is simplified, because a real funnel has more stages and variables. The logic holds: optimising for CPL without considering quality optimises the wrong thing.
What does this look like in practice?
For Naitors (PVC windows and doors), Google Search brought 56 enquiries at a CPL of €14.57 in one month (April/May 2026). CPL gives the price of an enquiry. The sales team sees the quality in the CRM, where every enquiry has an owner and a status. The full example is in the Naitors case study.
What is LTV:CAC and why do we measure it?
Once we have enough data (usually after 3–6 months of campaigns), we start measuring the ratio between customer lifetime value (LTV) and customer acquisition cost (CAC). A commonly cited rule for B2B services is LTV:CAC ≥ 3: every euro invested in acquiring a customer returns at least €3 in revenue over their lifetime.
Campaigns with a low CPL and low lead quality often push the ratio below 1. At that point, growth hurts the business model.
How do we measure lead quality in practice?
After the first contact, the sales team enters a simple qualification score. After 30 days we connect the advertising data with the CRM data and see which segments, creatives and channels bring premium leads, not just leads.
This feedback loop is what separates a system from guesswork. We then move the ad budget to wherever LTV:CAC is most favourable. How this works from ad to CRM is described on the lead generation page.
What is CPL still good for?
CPL is a good indicator for day-to-day campaign management. It is not enough for budget decisions. Without data on lead quality and conversion to revenue, advertising pays for a contact list with no clear path to profit.