The adaptive capacity of buildings is considered to be a crucial component when looking into the sustainability of the real estate stock (Hermans e.a., 2014). Market developments show increased demands for flexibility and sustainability by users and owners of buildings. Since 2014 a research project at the Delft University of Technology has been investigating the adaptive capacity of buildings. One of the interim results included an instrument to assess the adaptive capacity of buildings. The last version of this instrument FLEX 4.0 was presented in detail at the SBE16 Tallinn Conference, Build Green and Renovate Deep (Geraedts, 2016), including all flexibility key performance indicators. Another important research question to be answered in this continuous research project was: “Which flexibility measures have been actually used in practice by the (re)developers of office buildings”? To answer this question use has been made of all possible flexibility measures from the described FLEX instrument. The implementation of these possible flexibility measures was discussed with experts from practice and finally two in-depth case studies were performed in Amsterdam (Tuzgöl, 2016). This paper presents the final results of this research. They have led to a specific advice to project developers which flexibility measures should be applied at all times, which measures have been barely or not used at all in practice and therefore not recommended to apply, and finally which measures have not been applied but however desired by the project developers.