The transformation of our societies, boosted by the recent global pandemic, are setting new demands for built environments and buildings. So-called "flexible" buildings are becoming increasingly popular as the demand for versatile, multi-purpose spaces grows. They offer greater efficiency, allowing for a more dynamic and adaptable use of space. What does the flexibility exactly mean then? For example, it might be prefabricated modularity, adaptive reusability for other purposes, co-working spaces or just multi-usability, combining multiple walks of life in one structure. As the flexibility may consist of various different factors, what are the most important ones that define design for built environments in the future? How should the most novel technological advancements be taken into consideration in a way that creates value? What are the most interesting use cases for any buildings in the future?