Condition monitoring of a variety of systems is widely practised and yields valuable information. This is normally used for the organization of maintenance functions of industrial systems (or for treatment in the case of health care). At the executive level, asset management is an important consideration, and is usually based on financial grounds alone. In this work the methodology of system condition auditing based on fuzzy logic analysis is described, which results in an overall system condition metric. This makes fuller use of the information garnered from condition monitoring and provides additional management knowledge, enabling more informed decisions to be made about such aspects as plant refurbishment or replacement.