Why we track tenure, not just revenue.
Most agencies track monthly revenue, monthly new-business win rate, monthly margin per account. We track those too, but our primary internal metric is client tenure. Average months-on-the-book. Months since last new-engagement signed. Months retained per cohort. Why the metric we optimise for is the metric most agencies don't measure.
The numbers
From our Xero ledger, trailing 24 months:
- Adora Fertility: 80 months unbroken billing, multi-year fertility-network flagship
- Charleston's: 24 months continuous billing, capped-retainer commercial unchanged
- For Health: 23 months continuous billing
- JSW Australia: 23 months continuous billing
- PYBAR: 23 months continuous billing (through a Thiess acquisition integration)
- Berg Engineering: 22 months continuous billing
- PH Medical / Partnered Health: 21 months continuous billing
Forty-seven-month average tenure across our top accounts. 57.5% of our book is on long-term retainer.
Why tenure matters more than revenue
Three reasons.
1. The economics
Lifetime value × probability of renewal. A 24-month-tenured client with near-100% next-month renewal probability is worth multiples of a 6-month-tenured client renewing at 30%. The maths is straightforward and yet most agency growth plans optimise for the second number, not the first.
2. The agency operating model
Long-tenured clients let us invest in production efficiency. Brand-trained Imagen models pay back over months. Klaviyo segment programmes pay back over months. BigQuery dashboards take weeks to build properly and pay back over years. None of these are economic on a 6-month engagement; all of them compound on a 24-month engagement.
3. The signal it sends
Long tenure isn't a function of contract lock-in (we run month-to-month). It's a function of the client choosing to renew, every month, for two years. That signal, repeated 23 times by the same client, is the strongest performance evidence we have. It outweighs any case-study claim, any testimonial, any pitch deck.
What tracking tenure changes operationally
- We resist scope creep on existing accounts. A surprise charge that erodes trust on month 14 risks the next 24 months of compounding revenue. The maths doesn't justify it.
- We invest in senior strategist retention. Bait-and-switching senior people for junior delivery breaks the implicit contract that drives renewal. We pay senior people more than industry norms because the maths justifies it.
- We run capped retainers gladly. The Charleston's capped retainer looks like commercial restraint. It's actually commercial discipline, the cap is what protects the 24-month tenure trajectory.
- We refuse some new business. If the brief is "we'll be cheap and demanding for six months", we politely refer them on. The lifetime cost of taking that engagement is higher than the lifetime cost of declining it.
For brands evaluating us
If you're a brand looking for an agency that wants to be retained, not re-pitched, ask three questions:
- What's your average client tenure (in months, not "we have long-term clients")?
- What % of revenue is on month-to-month vs annual contracts?
- Do you mark up media spend?
If the agency can't answer the first question with a number, can't show retention data, or hesitates on media markup transparency, those are the signals. Long-tenured retainer-grade agencies are the agencies that have invested in being long-tenured retainer-grade agencies. Most haven't.
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