How can I enumerate valid email addresses using SMTP enumeration techniques

Question

For a security audit, I’m trying to verify email addresses on an SMTP server to check for potential misconfigurations or weak points. Could anyone provide guidance on how to perform SMTP enumeration effectively to identify valid email addresses without overloading the server?

If there are particular commands or techniques for this type of enumeration, or examples of common SMTP enumeration practices, it would be useful to know.