How to Choose a Marketing Agency: 15 Vetting Questions

$5.42 is the average cost per click in Google Ads in 2026, measured across more than 13,000 search campaigns in 23 industries. If the agency across the table quoted you a number far under that and could not say why your category would sit there, you have already found the first real question of the meeting. How to choose a marketing agency comes down to asking things whose answers can be checked afterwards, then noticing whether you were handed a structure or a reassurance.

Below are fifteen questions in four groups, with what a good answer sounds like. One caveat before you start: the benchmarks quoted here come from studies of search advertising and of large advertisers. They are calibration tools for judging a claim. They are not a forecast for your account.

How to Choose a Marketing Agency: Start With Who Owns What

Ownership is the easiest part of the vetting to get right, because the platforms have already documented the correct answer. Vague replies here are self-incriminating.

1. Who owns the ad accounts, the pixel, and the conversion history? You do. Google states that when a manager account takes ownership of a client account, owners get full administrative and data access privileges, and that the client account still owns its data and has the ability to remove ownership access by unlinking. Meta runs on the same logic: the assets live in your business portfolio, and partner access is granted out of it. A good answer walks you through that structure before you ask. A weak one is "don't worry, we set all that up for you."

2. Can I see the user list on every account we will touch? Ask during the sales process. The list shows how many people hold standing admin rights, whether someone who left two years ago is still on it, and whether your account shares a login with four others.

3. What will be hosted on your infrastructure rather than mine? Landing pages, forms, tracking subdomains, call tracking numbers, scheduling links. Anything sitting on the agency's side is something you lose in a separation, along with whatever history was attached to it.

4. Walk me through the offboarding, specifically. The answer you want names mechanics: accounts stay where they are because they were always yours, access gets revoked on a date, creative files and page exports are handed over, CRM field names survive. If the reply is that they would of course help with a transition, nobody there has run one cleanly.

The Questions About Time That Nobody Enjoys

Most of the disputes I have seen described between an operator and an agency are arguments about the clock. The buyer wants a verdict; the platform needs volume before a verdict means anything. Settle the timeline in writing before money moves, because retrofitting patience onto a bad month never works. The month six fight usually begins as a week two disagreement about what a number means.

5. How long before you will judge this, and what would make you stop sooner? New campaigns sit in a documented learning period where results swing hard and early averages are unstable. Anyone promising a verdict inside week one is contradicting the tools they work in. Listen for a window, a minimum volume of conversions inside that window, and the specific failure that would justify killing something early.

6. What is our conversion lag, and how does your reporting account for it? This question sorts operators from account managers. Google's help documentation explains that because conversions are reported by query date, CPA can look inflated and ROAS deflated, since the click and the conversion land on different days. If your sales cycle runs three weeks, last week's report is structurally pessimistic. A good agency says that unprompted and shows you a lag-adjusted view.

7. Which number will look bad in week three, and what will you say about it then? Asking someone to pre-commit to their own bad news is the cheapest honesty test available. Answers get specific fast, or they get evasive fast.

8. Which metric will you be held to, and which one will you refuse? A partner who accepts every metric has not thought about attribution. A partner who will only stand behind impressions and engagement is selling you numbers that do not predict revenue.

Where the Money Actually Goes

9. Do you ever buy media inventory yourself and resell it to me? This is now a mainstream governance question. The ANA defines principal media as the practice in which agencies purchase media inventory themselves and resell it to clients rather than acting solely as agents, and its 2026 research found that only 57 percent of marketers say their companies have guidelines governing principal media, while 90 percent say their top concern is whether recommended principal media is truly in their best interest, up from 79 percent in 2024. The ANA's remedy is to address the practice explicitly in the agency agreement and set approval requirements before such transactions occur. Asking is not an accusation. Getting a fuzzy answer is information.

10. What does your fee model reward when our interests diverge? A percentage of spend rewards spend, a flat retainer rewards keeping you on the roster, and performance fees reward whatever the attribution window happens to credit. Every model carries a bias, so the useful conversation is about which bias you can live with for the next year. We wrote up what each fee model actually incentivises if you want that argued out properly.

11. Where did the target CPL in your proposal come from? A good answer names a source and a range, then explains why your category sits above or below it. WordStream's 2026 study puts the average click-through rate in Google Ads at 6.64% with wide variance by industry, so a proposal quoting one confident figure with no provenance is quoting a hope.

12. What does the rest of the funnel have to do for this budget to work? Make them show the arithmetic. Here is the model I run, and you should re-run it on your own inputs rather than borrowing mine.

Assume a $12,000 monthly media budget and a $6 cost per click, rounding up from the search average quoted above for a competitive category. That buys 2,000 clicks. Assume 4% of those clicks become a form fill, which gives 80 leads at $150 each. Now pick a booking rate and a show rate out of your own CRM; I am using 45% and 70% here purely to make the arithmetic visible, which turns 80 leads into 36 bookings and 25 held conversations. At a 20% close rate that is 5 new clients on $12,000 of media, or $2,400 of media cost per client before any agency fee. Now move one input. If show rate falls to 50%, you hold 18 conversations and land roughly 3.6 clients, and media cost per client climbs past $3,300.

Those percentages are assumptions I picked for the demonstration. They are not findings. What the exercise reveals is that the two inputs with the most violent effect on the outcome, booking rate and show rate, both sit on your side of the handoff. An agency that cannot tell you which of your numbers has to hold is not doing this math, and follow-up speed is usually the first place it breaks.

The Questions About Who Actually Does the Work

13. Who touches the account day to day, and how many other accounts do they carry? You want a person, a role, and a number. The one on the sales call is rarely the one in the account, which is fine as long as you meet the second person before signing. When the account load is described as unknown, it is high.

14. What do you need from me weekly, and what happens when I miss it? Most stalled engagements involve a client-side dependency that quietly never arrived: call recordings, product photography, a sign-off, one CRM field. A good answer names the dependency, the day it is due, and the consequence when it slips.

15. What would make you resign the account? Anyone who has run delivery has ended a relationship and can say why in a sentence. A partner with no exit criteria has no quality bar, and you will discover that in month four rather than month one. If you want to hear how we answer these questions before you ask them, our application is where that starts.

Run the whole list in a single meeting and pay more attention to the shape of the answers than to their content. Ownership questions should come back as structures you can go and verify inside a platform interface within ten minutes. Timing and money questions should come back with a window, a threshold, or a source you can look up without asking permission. When you get a story where a structure belongs, you have learned what you needed, and you have learned it before spending anything. Then do the last piece of work: write the four or five answers that mattered most into the agreement itself. An answer given verbally in a sales meeting and never written down has a habit of changing by month three.

How to Choose a Marketing Agency: Start With Who Owns What

The Questions About Time That Nobody Enjoys

Where the Money Actually Goes

The Questions About Who Actually Does the Work

Sources

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