In the hierarchy of product effectiveness is one general area of design consideration that has avoided objective evaluation. This is serviceability, with its attendant subdivisions, maintainability and repairability. Most listings of design specifications refer to these areas without defining how the level of achievement is to be measured. This paper offers a heuristic method of quantitatively setting targets and checking for conformance in one area-maintainability-prior to and during the design phase. The method also provides a system to quantitatively audit, or qualitatively compare, existing machines.