How do you know where you actually stand? If you or your IT point person can't clearly describe your security posture today, or if your current IT provider/department can't give you meaningful reporting on the status of these layers, that's a signal. Not necessarily that something is wrong, but that you don't have visibility. And you can't improve what you can't see.
A third-party assessment gives you that visibility, a foundation upon which you can improve. Someone outside your day-to-day IT relationship looks at what's in place, what's missing, and what matters most given your specific business. The output should be a clear picture you can act on — whether that's with your current provider, a new one, or on your own.
The gold standard is a fully impartial reviewer with no financial relationship beyond the assessment itself. In practice, many small businesses get their first outside look from an IT provider — and that's a reasonable starting point, as long as the assessment stands on its own as a useful deliverable, not a sales pitch dressed up as a report.
For organizations that already have security measures in place, periodic third-party verification serves a different purpose: confirming that protections are functioning as intended and catching gaps that internal teams may have overlooked. The value of ongoing audits depends on your risk tolerance, regulatory environment, and the sensitivity of your data. It's a best practice, but not a requirement for every business, hence why we list it as the 9th (optional) layer.