The paper provides a comprehensive overview on which through-life cycle aspects of Functional Products (FP) are relevant to consider during development and later operation until end of life. The aspects, which are already proposed as part of the current definition of FP, are corroborated, and the additional new aspects found are proposed to extend the current definition of FP. An additional eight new aspects have been found, spanning, e.g., asset management, business model and research collaboration. Some of these new aspects may be relevant for the concepts of servitisation, through-life engineering services, product-service systems and industrial product-service systems as well. The practical implications of the results are that FP customers can improve their reasoning and requirement engineering together with FP providers. FP providers can, on the other hand, use the results to improve their long-term planning and activities from initial development activities (i.e. business case and requirement engineering) to operation at customer sites. The theoretical implications are that the additional new aspects and the proposed extended FP definition provide a foundation for researchers as well as indicating aspects/areas to further explore.