I have also described how, compared to most industrial products, the use phase of buildings and building materials is particularly crucial. They are long-lived and so their relationship to time is central. Can they be durable and/or gracefully re-absorbed into economic and ecosystem change? Buildings may be holding devices for materials, but like the human body or other dynamic ecosystems, the materials being held change over time; they change at different rates; and the holding patterns also evolve in response to need and context. Proper building design should consider all these things. As Brand (1994) has demonstrated, however, the contemporary architectural profession has fetishized the external appearance of buildings at the expense of both building adaptability and user needs. Studieswhich have been studiously ignored by architects and developersshow that buildings are rarely used for the purposes they were originally intended. To the degree that designers have been even partially concerned with new building use, they have reified the immediate needs of the prospective clients with little thought to changing needs and capacity for adaptation to unforeseen circumstances. Architectural design competitions are based exclusively on photographs taken before occupancy, and, according to a UK study, fewer than one in eight architects ever visit their buildings after occupancy. Post-occupancy evaluationa fancy term meaning user feedbackis a new field that has emerged despite architects, and is still far from the central design tool it should be. Only part of mainstream architectures failings, however, can be attributed to architects. The external focus of the design professions is encouraged by the whole development industry and property relationships which inevitably pit exchange-value against use-value. The power of money and the juggernaut of economic growth often