Summary form only given, as follows. Systems maintenance consumes a major proportion of the resources of information systems departments in most organisations. It is often argued that these resource requirements can be reduced by the adoption of particular technologies or methodologies, such as structured analysis or more recently object oriented technologies. The paper reviews these claims by examining some of the more basic issues of systems maintenance such as: (1) the basic definition of maintenance and the various types that can be identified; (2) the methods required for the effective management of maintenance; (3) design issues that favour maintainability; and (4) issues of measurement. Consideration of these issues leads to the conclusion that the most significant impact on systems maintenance costs are more likely to be derived from general improvements in the management tools rather than in the technical tools. Some progress towards evaluating these issues is then discussed.