I've built a few sales team for early stage startups, and invariably the question comes up: "Inbound sales is working. Will outbound sales work?"

The successful experiments I've seen look like this: hire 2 SDRs at the time, focus them exclusively on outbound, then measure their results to identify the CAC. Then, you can make a call if that CAC is something you want to scale.

The failed experiments look like this: the founder doesn't want to invest too heavily in something that might not pay off, so we hire 1 SDR and they have to commit 50% of their time to following up on low quality Marketing leads.

It's not so much about the number itself, but more about the experiment design that will give you clear results