The Due Diligence Most People Skip When Choosing a Marketing Partner

I am going to write this piece against my own commercial interest, which feels like the right way to start.

Choosing a B2B marketing partner is not a simple procurement task. It is a decision that will shape pace, communication flow, energy, strategic thinking and ultimately the commercial momentum you achieve over the year. You will spend real time with these people. You will share context, challenges, internal dynamics and pressure with them. So yes, there needs to be connection. You need to feel you can work with them and not dread the next meeting.

But chemistry on its own is not enough.

A smart pitch and a polished deck do not prove capability. Plenty of agencies can speak well about marketing. Very few can point to evidence that they have meaningfully moved outcomes inside real B2B environments. You are not buying theatre. You are buying judgement. And judgement is revealed through evidence.

It is also worth saying clearly that this does not mean you only choose people who have done your exact category before. Sometimes the most valuable contribution comes from outside your immediate pattern. A fresh perspective on an old problem can be the unlock. The key point is not sameness. The key point is whether they understand the shape of B2B: complex buying paths, slower conversion cycles, multiple stakeholders, rational justification, and the need for marketing to tie back to revenue reality rather than surface impressions.

Why this got harder

There is a trust problem, and AI is not helping.

The volume of outbound I receive every week has quietly destroyed my ability to read signal into it. One automated sequence has essentially been having a conversation with itself since the spring.

More importantly, it has become genuinely difficult to decipher expertise when there is enough information available for almost anyone to present basic competence. What used to be the natural signal of a skilled supplier, the ability to write about the problem intelligently, has been blurred by the generic confidence manufacturing that AI now enables.

Everyone sounds like they know what they are doing. The written proposal is no longer evidence of anything. Which pushes the burden back onto the questions you ask in the room.

So interrogate experience rather than assume it. Not in an adversarial way. Not in a cynical way. But in a grown up way that recognises the cost of being wrong is real.

The checks

Call their old clients. This is the simplest validation step and most people never do it. One short conversation with someone who has paid them actual money will tell you more than any case study. Not the client they present. Choose one they did not present.

Show me the people, not the pitch team. Agencies bring their best theatre to a pitch. The day to day reality will be whoever is actually doing the thinking and execution. That team might be very different. You need to know names, experience, and where judgement sits.

Metrics or it did not happen. Anyone can show a slide of a result. The real proof is in the movement. What shifted over time? What changed because of the work? B2B is systemic. If they cannot show a delta, they cannot prove they influenced anything.

How long do clients actually stay? B2B outcomes take time. Strong client tenure means they are useful. Constant churn is a story all by itself.

Tell me what failed. If they cannot discuss a failure, they are not reflecting. And if they are not reflecting, they are not improving. The failure story is often the more valuable one.

Interrogate me back. Real operators ask questions. They try to understand context, constraints, legacy issues and politics before they prescribe. If they do not do that, they are not diagnosing. They are performing.

Where are the assumptions? Any plan worth something is built on assumptions, conversion logic, friction points and time. Show me the skeleton of your thinking, not the surface.

Ask what they would do with AI, and listen for the honest answer. The wrong answer is a list of tools. The right answer explains what they now do faster, what they refuse to automate, and what they are still working out. Anyone claiming AI has solved their delivery model is selling you a position rather than describing their practice.

Can I sit in a room with you for six months? This is not about likeability. It is about energy. You will spend real time with these people. If the dynamic is heavy on day one, it will be unbearable by day ninety.

Why it matters more than it looks

B2B outcomes take patience, iteration and alignment. That is why these questions matter. Because in B2B, the cost of being wrong is not simply a failed campaign. It is lost time, lost credibility with sales, and lost conviction at the board table.

When you stand in front of your board, your decisions are the proxy for your competence. They do not see the constraints you navigated or the nuance behind the scenes. They see the quality of your outcomes. If you commit budget to the wrong partner because you skipped the basic due diligence, that does not read as optimism. It reads as poor judgement. And poor judgement drains trust fast.

This is not about suspicion. It is about responsibility.

The work you do, the money you commit and the partners you choose reflect directly on you.

Doing this properly protects your budget, your results and your reputation in the room that matters most.

And if you are ever sitting across from me, ask me all of the above. I would think less of you if you did not.