Modern manufacturing systems and process plants are complex, highly optimized systems, for which seemingly small changes in the operating conditions of a component can have significant impact on the overall performance of the system. In these environments, even though any component breakdown could interrupt the whole process, the cost associated with unnecessary component replacement would lessen the plant's profitability, and should be prevented as well. Therefore, the past maintenance strategies of corrective and/or preventive maintenance, may prove to be costly, presenting the opportunity to predictive maintenance techniques to be utilized. A clear understanding of predictive maintenance can help design and manufacture components with preventive maintenance features in mind. This article reviews the state-of-the-art on predictive maintenance and introduces the new concept of reliability-centered maintenance.