This decision gets argued emotionally and decided badly. It is a straightforward trade between speed and ownership, and the right answer depends almost entirely on your monthly spend.
The comparison
Where each one wins
Own BM wins when: you have time to warm up, your spend is modest, you need full data ownership for compliance, or you are building a long-term brand asset.
Agency access wins when: you need meaningful daily spend immediately, you are testing a new market and cannot wait three weeks, or you need support paths that self-serve accounts do not have.
The spend threshold
Run the arithmetic once and the decision usually makes itself.
At 4% commission:
Below roughly $10k/month, commission is a reasonable price for speed. Above it, you are paying agency-salary money every year for a container you cannot take with you.
The structure most operators actually run
Not one or the other — both.
- Own BM as the permanent home for pixels, pages, catalogues and long-term data.
- Purpose-bought accounts as spending vehicles that carry the trust needed for immediate volume.
- Redundancy: at least one warmed spare account ready before it is needed.
This gives you the speed of pre-trusted accounts without handing your long-term data assets to a third party, and without a percentage of every dollar you spend leaving the business permanently.
The question to ask a provider
"If I spend $100k next month, what do you charge?" A one-time price is the same number regardless of the answer. A percentage model gets more expensive precisely as you get more successful — which tells you exactly whose growth the model is designed to serve.