The auditor is required to follow the guidance provided by the Standards, without exception.

The auditor is generally required to follow the guidance provided by Standards with which he or she is familiar, but will not be held responsible for departing from provisions of which he or she was unaware.

The auditor is generally required to follow the guidance provided by the Standards, unless following such guidance would result in an audit that is not cost-effective.

The auditor is generally required to follow the guidance provided by the Standards, and should be able to justify any departures.