The enormous recent increase in the cost of building materials and the current supply shortages highlight how wasteful we have become in farming our scarce resources. It has long been common to reuse materials from buildings that are no longer in use, while natural materials such as stone, clay and wood eventually decay and are returned to the material cycle. However, the complexity of new synthetic materials means they are not returned to the material cycle, so demolition now generates tons of hazardous waste or landfills. The practice of reusing, replacing, leasing, repairing or renovating materials is heavily promoted but rarely applied, partly because of legal restrictions. New legislation and new ways of thinking are now needed if we are to reduce the quantities of waste we are producing.