How to choose a digital marketing agency (and what to ask before you sign)

Ask to see a live account before you talk about yours. Any agency can describe a strategy on a slide. Far fewer will open a real client's ad account and reconcile the spend against that client's own sales records, on the call, while you watch.

When we show a result, we show the working. $3,014 of ad spend turned into $145,626 of work for Swift Air, a ducted heating installer, between April and October 2026: a 48.3x return on ad spend, or $232 of ad spend per job won (the full numbers are on our Swift Air case study). $53,198 of ad spend turned into $585,692 of Meta-reported sales for KKANG, an ecommerce brand, over 18 months: an 11.0x Meta-reported return, tracked separately from its Google-reported numbers because the two platforms can claim the same order (the KKANG case study has the full breakdown).

Neither result is unusual for an agency with a few years in the account. What is unusual is an agency willing to show you where the number came from. A logo wall with no dates and no spend figures is a highlight reel, not evidence; the agency has picked its best month from its best client and left out the rest. If an agency's results page shows logos and nothing else, ask for the account behind one of them. If they cannot produce one, that is your answer.

The person who pitches you is rarely the person who runs your account. Ask by name: who builds the campaigns, who answers if something breaks on a Friday, and how many other accounts that person carries.

A strategist carrying twenty-five accounts has, at best, a few hours a month for yours. A specialist carrying six can watch your account daily. Neither size is automatically wrong, but the number itself tells you what kind of attention your budget buys. Ask for it directly: how many accounts does my day-to-day contact manage, and who else is in the group chat with me?

Watch for a pitch that names senior people on the call and junior people in the contract. If the person presenting results to you will not be the person managing your spend, ask to meet the person who will, before you sign, not after.

Read the notice period first, before anything about strategy. A month-to-month agreement with 30 days' notice protects you if the work goes nowhere. A six or twelve-month lock-in protects the agency, not you.

You might read a 30-day notice period as a sign the agency does not trust its own work. It is closer to the opposite: a short notice period only works for an agency confident enough to keep earning the account every month, rather than relying on a contract to keep a client who wants to leave.

Check what happens to the ad account, the pixel data and the creative files if you leave. Some agencies build campaigns inside their own agency-level ad account; if that account closes, your campaign history and audience data close with it. Ask where the account lives and whether you keep access if you walk away. Business.govt.nz has a plain-language contract checklist worth running any services agreement through before you sign.

Ask what is held still if results disappoint: does the fee change, does the scope change, or does nothing change until a review date you both agreed on. If the answer is vague, that vagueness is doing work for the agency, not you. Fee itself is a separate conversation: our guide on how much a digital marketing agency costs in NZ sets out the market ranges to check an agency's quote against.

Decide what a weekly or monthly report looks like before the first invoice, not after the first disappointing one. Ask for a sample report from an existing client, names blacked out if needed, and check it ties ad spend to leads or sales, not just impressions and clicks.

Cost per lead and return on ad spend are the two numbers that matter most for a service business. If an agency's sample report shows reach and engagement and nothing about cost per result, ask why those numbers are missing before you ask for a bigger budget. Our own ad spend calculator shows the maths behind cost per lead and return on ad spend, if you want to check an agency's numbers against your own before you sign.

Agree the reporting cadence in writing: weekly for a new account in its first two months, monthly once it has settled. Nothing about the campaign needs to change for that schedule to hold; it is a reporting decision, not a performance one.

A few patterns predict trouble before the first result comes in. None of these is a strategy problem. They are agreement problems, and every one of them shows up in the first conversation if you ask the right question.

• No source for any number on their results page. A return on ad spend or lead count with no date, no spend figure and no link to a case study is a claim, not proof.
• A lock-in longer than the time it takes to see a real result. Most paid-ads accounts need six to eight weeks of data before anyone can judge them fairly; a 12-month lock-in with no exit before then shifts the risk onto you, not the agency.
• Vague answers about who does the work. If the account manager on the call cannot name who builds the campaigns, the agency has not decided either, and your account will be whoever has a spare hour that week.
• Reporting that stops at impressions and clicks. Those numbers are easy to grow and say nothing about whether the business made money.
• A guarantee with no mechanism behind it. "We guarantee leads" means nothing without a definition of what counts as a lead and what happens if the number is not hit.

Bring this list to the first call. A good agency answers every line without flinching. A weak one redirects to strategy talk instead, because strategy talk cannot be checked on the spot.