Opinion

Why we’ve worked with the same client for 15 years — and why that’s rare

Sean Cummins, founder of Cummins and Partners, explains how long-term agency/client partnerships require more work, not less, and ponders why such relationships in the industry have become so rare — and what we’ve lost as a result.

SEAN CUMMINS

February 4, 2026 9:40

Why we’ve worked with the same client for 15 years — and why that’s rare

Sean Cummins - author

Fifteen years ago, I shook hands on our first agency client.

There was no pitch theatre. No procurement marathon. No credentials deck refined by committee. Just a shared belief that if we worked hard, stayed honest and backed each other through change, the relationship would last.

That client was Stellantis Australia. This month, they reappointed us again.

In an industry where the average agency–client relationship barely survives two to three years, a 15-year partnership is almost anomalous. Particularly in automotive — one of the most complex, cyclical and globally influenced categories in advertising.

It’s worth asking why long-term relationships have become so rare — and what we’ve lost as a result.

The industry has optimised for change, not value

The modern marketing ecosystem rewards motion. New agencies promise reinvention. New leaders want a visible break from the past. Reviews are scheduled as a matter of hygiene, not dissatisfaction. Procurement cycles prioritise cost certainty over accumulated knowledge.

None of this is irrational. But collectively, it has created an industry that treats relationships as disposable — and institutional memory as a liability rather than an asset.

The irony is that the work clients say they want — smarter strategy, stronger commercial outcomes, deeper brand equity — is almost impossible to achieve without continuity.

Trust compounds. Understanding compounds. Results follow.

Long-term partnerships don’t endure because nothing changes. They endure because everything does.

Over 15 years, Stellantis has navigated brand launches, portfolio shifts, market volatility, global restructures, leadership changes and evolving consumer expectations. So have we.

What longevity allows is not complacency, but fluency. We understand the category deeply. We understand the pressures inside the business. We know when to push and when to protect. We don’t need to relearn the fundamentals every 18 months — which means more energy goes into solving the next problem, not restating the last one.

That depth doesn’t show up in credentials decks. But it shows up in decision-making quality.

Long-term relationships demand more, not less

There’s a misconception that long agency relationships exist because expectations soften over time. The opposite is true.

When you work together for years, there’s nowhere to hide. Short-term thinking is exposed quickly. Tactical wins without strategic intent don’t survive scrutiny. Trust only holds if performance does.

Longevity requires commercial honesty, mutual accountability and the willingness to evolve together — creatively, strategically and structurally.

It also requires resisting the temptation to chase novelty for its own sake.

The best work often comes after the honeymoon

Some of the strongest thinking in any relationship happens well after the initial excitement fades. Once trust is established, conversations become more direct. Decisions become faster. Risk becomes more intelligent. The work benefits. That’s when agencies stop performing for clients and start working with them.

In a category like automotive — where investment cycles are long and brand equity is built over decades — this matters enormously.

Maybe the question isn’t, “when should we review?” Perhaps the better question is: what are we optimising for?

If the answer is short-term optics, then frequent change makes sense. If the answer is enduring value, consistency deserves more respect. Fifteen years isn’t a target. It’s a by-product of alignment, trust and shared ambition over time.

Those things can’t be rushed. And they can’t be replaced.

Note: For those advertising history buffs, Cummins and Partners has been an agency in two stanzas of approximately 15 years each. This year is our 30th year as an independent, Australian owned agency with offices in Melbourne, Sydney and New York.