Every founder runs this math at some point: the agency retainer looks expensive next to one salary. The comparison is almost always wrong, because it prices a person against a system. Here is the honest version.
What in-house actually costs
The salary is the visible line. The invisible ones: design tools and scheduling software, a second hire the moment video enters the plan, management time nobody bills, hiring risk when they leave with your momentum, and the ceiling of one person’s ideas repeated monthly. A genuine in-house content function is three salaries and a manager before it matches what a retainer ships.
What an agency actually costs
The retainer, plus the coordination tax of working with an external team, plus the risk of picking badly. What you rent: a full stack of strategist, writer, designer and editor, production systems including AI pipelines that collapse creative costs, and pattern recognition from running many accounts, which is the asset no single hire can offer.
The stage-based answer
Early stage with founder-led voice: in-house or founder plus freelancer, because authenticity beats polish. Growth stage needing volume and consistency across platforms: agency, because systems beat individuals. Scale stage: hybrid, an internal brand custodian directing an external production engine. The mistake is ideology, choosing a model because of how it feels rather than what the stage demands.
How to judge either option
Same test both ways: does the reporting connect content to enquiries and revenue, or does it stop at reach? Our social practice reports the former, and the ten questions work on internal candidates too. Whoever answers them better wins your budget.