In the coming decades the systems for generation, transmission and distribution of electrical power undergoes significant changes due to technical, economical, social and environmental drivers and developments. In this paper we discuss how these changes affect future maintenance. First of all there is a continuous evolution of maintenance practice as such. Secondly maintenance practice have to adapt to the changes in power system design and operation. We will show that maintenance of the future infrastructure involves more than fixing defects: it starts with the design of components and grid. Maintenance involves not only intelligent corrective and preventive maintenance activities but also preventive action in terms of design and operational practice. Based in this evaluation we conclude that future maintenance involves a smart mix of some or all of 4 maintenance strategies: 1) maintenance free component design, 2) system design including maintainability, 3) effective and efficient maintenance processes and 4) controlled stress system operation