Smart Retrofitting in maintenance indicates the development of maintenance services through the retrofitting of legacy devices with the functionalities of data collection, data communication and data processing. Many companies nowadays desire to retrofit their assets through the implementation of Prognostics and Health Management (PHM) services to assist in better predicting their future state and making timely and sound decisions. In this context, this work presents the PHM center developed by the company Celsia in the Alto Anchicayá hydropower plant and discusses the available approaches for estimating the value brought by PHM investments. Even if different works can be found in the literature with this purpose, only the economic feasibility of PHM implementations is generally considered. Whereas, in value-based decision-making different dimensions are embraced and not only the performance and cost ones. Therefore, the need of a value model to support decision-making concerning PHM implementations is presented and the potential of System Dynamics for this purpose is discussed.