By developing and using modular product families, large savings can be achieved through reuse and combinability along the entire value chain of a company. Since these potentials often have a very long-term character, the lifetime of a modular product family should be as long as possible. Change drivers, such as changing customer and production requirements, however, result in changes having to be made to the initially developed modular product family, which not only causes a great effort but also prevents the long-term benefits from being fully exploited. With the Change Allocation Model, we introduce a tool that makes it possible to align the essential future changes to the product architecture and to identify and redesign the change-critical components taking into account the existing component variety of the product family. This enables future changes in variety to be considered in the product architecture and a future robust modular product family to be developed. The new visualization is illustrated using the example of a product family of pressure regulating valves and is finally discussed with regard to further potentials and challenges.