How to tell if an agency actually works or if they're learning on your dime

At Sally, we’ve run 20+ outbound projects just this year for B2B teams across SaaS, fintech, and enterprise. And there’s a pattern we see over and over again: many companies only come to us after they’ve already burned money with another agency.

The scenarios are almost always the same:

The $20k “guru” retainer. Someone who built a name years ago, still sells on reputation, but has no real incentive to deliver or retain clients.
The $1,500/month starter agency. “They seem to do the same thing, why overpay?” Until you realize the difference the hard way.

So how do you separate the agencies that deliver from those that experiment at your expense?

Here’s a checklist I’d use when evaluating any partner agency (not just in sales):

1/ Recent, verifiable case studies

Look for at least 3–4 case studies less than six months old, ideally in your industry, with client contacts you can actually check.

If they hide behind “strict NDA” excuses, that’s a red flag. Truly satisfied clients are usually happy to confirm the results.

2/ Clear resource allocation

Who exactly will work on your project, and how much of their time is dedicated to it?

If one person is stretched across 3–4 clients, don’t expect meaningful results—especially at the start, when dozens of hypotheses need testing.

3/ Transparent processes

Outreach (or any form of growth work) isn’t “set it and forget it.” It’s constant hypothesis testing, iteration, and conversion tracking.

Ask: How do they make decisions? What does reporting look like? How are leads handed over? Can they show you examples of follow-ups after meetings?

4/ Strategy before contract

A solid team should walk you through at least a one-month plan upfront: which hypotheses they’ll test, what tactics are worth trying, and which ones aren’t.

If their answer is basically “anything might work,” you’re paying them to learn at your expense.

5/ Access to unique data sources

Pulling leads from Apollo or Sales Navigator isn’t enough anymore. Experienced agencies can parse niche sources or leverage databases others can’t touch (conference lists, local directories, industry-specific sources).

That’s often where the real opportunities are.

6/ The contract itself

The maturity of an agency is visible in their contract. A three-paragraph “napkin agreement” usually means they haven’t clearly defined what they actually deliver.

Choosing the right partner is less about promises and more about structure, process, and proof. Use this checklist, and you’ll quickly see who’s worth your budget—and who isn’t.

✍️ At Sally, we’ve helped 20+ teams set up outbound the right way — with fresh data, tested hypotheses, and processes that actually scale.

📚 Curious what that looks like? Check out our case studies here: