The pitch for an outbound agency is that they have done it before and you have not. That is usually true, and it is worth something.
The pitch against is that you are renting a capability you could own. Also true, and also worth something.
What almost nobody does is put numbers on either side, which is why this decision gets made on instinct and regretted around month eight. Here is the model.
What a retainer actually covers
Typical B2B cold email retainers run $3,000 to $8,000 a month, with performance and per-meeting models alongside. Unbundle a mid-range one and you find roughly this:
| Line item | What it involves | Rough in-house equivalent |
|---|---|---|
| Infrastructure setup | Domains, mailboxes, DNS, warmup | $150–$400/mo at 50 mailboxes |
| List building | Sourcing and verifying contacts | $100–$300/mo in data |
| Copywriting | Sequences, variants, iteration | Part of somebody’s job |
| Sending and monitoring | Campaign management, deliverability | Part of somebody’s job |
| Reply handling | Triage, qualification, booking | The expensive part |
| Reporting | Weekly or monthly | An hour a week |
Tooling and data across that list comes to somewhere around $400 to $800 a month. The remainder of the retainer is labour and margin, which is the correct way to think about it. You are buying somebody’s time and their prior experience, not their software.
That framing matters because it tells you what you are actually comparing: an agency’s labour against your own, plus the cost of your own learning curve.
The in-house model, honestly
The mistake people make here is pricing the tools and calling it done. Tools are the cheap part.
Tooling and data. $400 to $800 a month for a working programme at moderate volume, covering infrastructure, sequencing, data and warmup.
A person. This is the real number. Somebody has to build lists, write sequences, watch deliverability and handle replies. If that is a dedicated SDR, fully loaded cost in the US is $70,000 to $95,000 a year, call it $6,500 a month. If it is a founder or a marketer doing it alongside other work, it is perhaps 40% of their time, which is not free even though it never appears on an invoice.
The learning curve. First-time in-house programmes typically take three to five months to reach the performance an experienced agency hits in six weeks. That gap is a real cost and it is the single strongest argument for hiring one.
So in-house is roughly $900 to $1,500 a month if an existing person absorbs the work, or $7,000 to $7,500 a month with a dedicated hire. Against a $5,000 retainer, the comparison is not obvious in either direction, which is exactly why people get it wrong.
Where the crossover sits
| Scenario | Agency | In-house | Better |
|---|---|---|---|
| Testing whether outbound works at all | $5,000/mo, results in 6 weeks | $1,000/mo, results in 4 months | Agency |
| One channel, steady volume, existing team | $5,000/mo | $1,200/mo absorbed | In-house |
| Scaling past 100k sends a month | $8,000+/mo | $7,500/mo with a hire | In-house |
| Multiple markets or languages | Depends on their coverage | Expensive to staff | Agency |
| Highly technical or regulated product | Often poor fit | Better | In-house |
The pattern underneath is time horizon. Under six months, the agency wins on almost any configuration, because you are buying speed and avoiding a learning curve you will not have time to climb. Past twelve months, in-house wins on almost any configuration, because you have paid for the learning curve once and the tooling cost is a rounding error against the retainer.
Between six and twelve months is a genuine judgement call, and it usually turns on whether the work is core to your business. If outbound is how you acquire customers permanently, owning it is strategic. If it is one experiment among several, renting it is sensible.
The costs nobody quotes
Four things distort the comparison and none of them are on a proposal.
The knowledge leaves. Everything the agency learned about which segments respond, which openers work, which objections come up, walks out with them. Some agencies hand over a document. Most hand over a spreadsheet of results, which is not the same thing.
The infrastructure may leave too. If the agency registered the domains on their registrar account, your warmed sending infrastructure is theirs. Nine months of domain reputation evaporates and you start from zero. This is the single most expensive mistake in the category and it is entirely avoidable in the contract.
Ramp time gets paid twice. If you hire an agency for six months and then bring it in-house, you pay for the ramp again. The in-house team does not inherit the agency’s sender reputation, their sequences or their judgement.
Shared attention. An agency running twenty clients is not thinking about you most days. That is fine when the playbook is standard and costly when your market is not.
The hybrid nobody proposes
There is a third option that tends to beat both and rarely gets pitched, because agencies do not sell it and software vendors do not staff it.
Own the infrastructure and the tooling. Domains in your registrar account, mailboxes in your platform, data in your workspace. Then hire the agency for the labour on top of your stack rather than theirs.
You pay a somewhat lower retainer because they are not marking up tools. You keep the sending reputation when the relationship ends. The lead data stays yours. And bringing it in-house later becomes a staffing decision rather than a rebuild.
Most agencies will agree to this if you ask before signing. Very few will offer it, because the tooling markup is real margin and owning the infrastructure is real retention.
What to ask before signing
- Who registers and owns the domains, and what happens to them at the end?
- Which tools are we paying for through you, and at what markup?
- What do we receive at termination: sequences, results, segment learnings, the list?
- Who writes the copy, and do we approve it before it sends?
- What is the ramp period, and is it billed?
- How many clients does the person on our account also run?
The domain question is the one to lead with. The answer tells you a great deal about how the relationship ends, which is the part you cannot renegotiate later.
The short version
Agencies win on speed and on avoiding a learning curve, which makes them the right answer for anything under six months and for markets you cannot staff. In-house wins on cost past a year and on owning the capability, which matters if outbound is how you acquire customers rather than something you are trialling.
The tooling difference is smaller than either side implies. A working stack is $400 to $800 a month and a retainer is $3,000 to $8,000, so what you are really buying is labour and experience. Price it that way and the decision gets considerably clearer.
And whichever way you go, own the domains.
Next: who owns the domains, and why it matters, or how many mailboxes a programme needs.
Frequently asked questions
How much does a cold email agency cost?
Most B2B retainers sit between $3,000 and $8,000 a month, with per-meeting and performance models alongside. Of that, roughly $400 to $800 is tooling and data; the rest is labour, experience and margin.
Is it cheaper to run cold email in-house?
On tooling, yes, by a wide margin. On total cost, only if an existing team member absorbs the work or you are past roughly a year, at which point you have paid the learning curve once rather than renting it monthly.
How long before an in-house programme performs?
Three to five months for a first attempt, against about six weeks for an experienced agency. That gap is the main thing a retainer buys.
Should a startup hire a cold email agency?
If you are testing whether outbound works for your market at all, an agency gets you an answer faster and the answer is worth the money. If outbound is already proven and you are scaling, in-house is usually cheaper within a year.
What happens to my domains when an agency contract ends?
It depends entirely on whose registrar account they sit in. If they are the agency’s, you lose the warmed infrastructure and the sender reputation with it. Settle this in the contract before you sign.