The comparison is usually framed as salary versus retainer, and that framing is the reason the decision so often turns out wrong.
What a hire actually costs
Take the salary and add recruitment (a month of effort or an agency fee), onboarding (three months at reduced output), tooling, leave, insurance, management time, and the cost of the next hire when the scope grows beyond one person's capacity. A conservative multiplier on the first year is one and a half times the salary — and the number is higher for specialist roles.
Then there is the risk that gets discussed least: a hire is a bet on a workload estimate made before the work arrived. If the estimate is wrong, you have a person with the wrong scope, and both outcomes — carrying the cost or ending the role — are expensive.
What a partner actually costs
A retainer buys a defined scope with named owners, a weekly report and a price that was agreed in writing up front. The variable parts are supervision time and the cost of switching if the fit is poor, which is real but bounded.
What a retainer does not buy is a person who grows with you into roles you have not imagined yet. Depth in one specialist area — the kind you get from a strong individual contributor who also learns your customers — is genuinely hard to buy as a service.
The hybrid that usually wins
Keep the judgement in-house and take the volume outside. One person on your side owns the standard, signs off the outputs and answers questions; the partner runs the repeatable execution against that standard, and flexes up or down without a hiring cycle.
This works because the expensive part of operations is not the doing — it is the knowing what good looks like. Hold that, delegate the rest, and the maths stops being a close call.
The questions worth asking either way
- If volume doubles next quarter, what happens to cost — and to delivery?
- Who exactly reviews the work before it reaches a customer?
- What happens if we stop in ninety days? What do we keep — process, data, tooling?
- Which single number will tell us in six weeks that this was the right call?
If a candidate or a partner cannot answer all four in a sentence each, you are still comparing prices rather than options.