At a high level, there are three types of audits: internal, external, and IRS. Of course, you have no control over when the IRS comes around, but the right mix of internal and external checks can help you keep your costs under constant scrutiny while keeping your books in order — which can't hurt if Uncle Sam does decide to take a dive into your telecom records.

Let's take a look at internal and external audits, which you can control and use to monitor your telecom spend.