Platform-based product development is about sharing components and product architectures between products in a product family to save costs and free engineering resources. The intension is that the components and product architectures must be shared both across existing and future products, but continuous product family evolution challenges this strategy. The concept of continuous platform development is based on the fact that platform development should not be a one-time experience but rather an ongoing process of developing new platforms and updating existing ones, so that product family evolution does not make the platforms irrelevant. This research is based on case studies and applications in the two Danish companies, LEGO and Grundfos, where several platform development projects have been followed. LEGO is exceptional for their long experience with platform development and maintenance, while Grundfos is relatively new within this area. This study puts emphasis on platform projects and defines such projects as something very different from product development projects and more similar to industrial research projects, due to the fact that they are continuous activities with relatively low risks and investments but also with relatively fuzzy results. When looking for new platform projects, it is important to make sure that the company and market is ready for the introduction of platforms, and to make sure that people from marketing and sales, product development, and downstream departments are all consulted. Platform ideas originate primarily from experienced workers, managers, or platform thinkers. Platform projects are presented regularly for future users and decision makers in structured presentations consisting of both quantitative estimates of costs and benefits and qualitative platform concept descriptions. This happens in a structured process, where platform projects are developed in parallel and prioritized in a stage-gate process. When platform projects end the responsibility of the platform components is passed on to the platform maintenance organization. Product developers can add new platform components and clean-up and replacements of platform components are organized. Platform performance can be evaluated based on platform component usage and growth. Platform development is effectively split from product development, but platform project are aligned through constant presentations and product developer involvement. When the two processes are brought back together timing of platform project is essential because it must be ready in time – too early starts can however make the platform irrelevant.