Facebook advertising works when you know what a customer is worth to you and can tell whether the campaign produced any. It fails, expensively, when a business boosts posts, watches the likes rise and never establishes whether anyone bought anything. The difference is entirely in setup and measurement rather than budget.
Four decisions determine the outcome.
Decide the objective before the budget
Awareness, enquiries and sales are different campaign objectives that the platform optimises for differently. Choosing the wrong one produces cheap results that are worth nothing.
Boosting a post is almost never the right choice for a business trying to sell. It optimises for engagement, which is the metric least connected to revenue.
Know what a customer is worth
Work out the profit on a first sale and what a customer is worth if they return. That figure is the ceiling on what you can pay to acquire one, and it is the only way to judge whether a campaign succeeded.
Then track cost per enquiry and the share of enquiries that become customers. Cheap enquiries that never buy cost more than expensive ones that do.
Target narrowly and expect creative to fatigue
A specific audience defined by location, interest and behaviour outperforms a broad one, because you are not paying to reach people who cannot buy. Start narrow and widen once something works.
The same advert shown repeatedly stops working. Budget for producing new creative rather than treating it as a once-off cost, and change one variable at a time so you know what caused a difference.
Send traffic somewhere specific, and respect the data rules
A campaign for a service should land on a page about that service, not a homepage. Most of what businesses pay for is wasted at this step.
Using customer lists for targeting and tracking visitors brings obligations under the Protection of Personal Information Act, overseen by the Information Regulator: a lawful basis, transparency and a working opt-out. Advertising claims must also be substantiable under the code administered by the Advertising Regulatory Board.
Frequently asked questions
Is boosting a post a good idea?
Rarely for selling. It optimises for engagement, which is the metric least connected to revenue.
How do I know if a campaign worked?
Compare cost per enquiry and conversion to customer against what a customer is worth to you in profit.
Should I target broadly or narrowly?
Narrowly at first, so you are not paying to reach people who cannot buy. Widen once something works.
Why does my advert stop performing?
Creative fatigue. The same advert shown repeatedly stops working, so budget for producing new material.
Where should the advert send people?
A page specific to what the advert offered. Sending traffic to a homepage wastes most of what you paid.
Further reading
Originally published in April 2018. Updated September 2026 into practical guidance on running paid social campaigns.
