Brand argues that many great buildings achieved their greatness by gradual stepwise evolution over time. New buildings need to be designed with the expectation that they will evolve, because they usually outlive their initial use. Even if a building does not change its use (e.g. it remains the same university department), the needs of its users will change and the building will need to adapt. This should be done, for example, by making sure that changing the space layout in the building is possible without changing the structure.

Almost no buildings adapt well. They’re designed not to adapt; also budgeted and financed not to, constructed not to, administered not to, maintained not to, regulated and taxed not to, even remodelled not to. But all buildings (…) adapt anyway, however poorly, because the usages in and around them are changing constantly.

See also: housing