Our cities have to expand either horizontally or vertically to accommodate the growing population and urbanization trends. Meanwhile, our needs, demands and desires evolve over time. This makes sustainable development and adaptability more relevant than ever. However, a main problem with adaptability is the additional investment costs against the lack of additional revenues. This lowers the financial return and disincentivizes to invest in adaptable developments. This claim is based on linear financial models that calculate on a rather short-term basis and only take the first function into account. The added value of the possibility to adapt to another function is not included in these financial models yet. The aim of this thesis is to investigate different approaches towards adaptability and business cases that are needed among long-term owners specifically to incorporate the added value of adaptable features. A hybrid research consisting of literature research combined with a case study on adaptable tall buildings will be executed, to identify important adaptability features, and how to better incorporate them in a business case. Interviews have been held with both stakeholders of the selected cases, as well as with different professionals in the built environment concerning a long-term business case. The results have shown that a building should not be regarded as one object, but merely as an ensemble of different building elements, each with a different lifespan. In addition, demountability has shown to be inherently connected to adaptability, and as means to achieve a more circular economy. By delivering a set of conditions on a technical, financial, organisational and a broader field, it is strived to contribute to increased implementation of adaptability in practice. By elaborating a roadmap for a more long-term business case, it is hoped to contribute to a smooth transition towards a more circular economy. In addition, this research aims to raise awareness, understanding and create incentives for adaptability possibilities.