This Article identifies the various ways in which property law provides special protection for existing uses, explores the possible justifications for this protection, and argues that none of them support the strong protection that existing uses currently enjoy. Various land use doctrines, from zoning, to the vested rights doctrine, to amortization rules for prior non-conforming uses, all assume that the government cannot eliminate existing uses without paying compensation. The Article asks whether this result is compelled either by constitutional rules or by normative considerations. Neither the Takings Clause nor the Due Process Clause requires this level of protection for existing uses. Normatively, many of the obvious-seeming justifications dissolve on closer inspection. Concerns about reliance on government regulations, and underlying principles of fairness, are not conceptually different for regulations prohibiting future uses and regulations of existing uses. Nor is the extent of economic loss necessarily greater for one than the other, even though regulations of existing uses involve out-of-pocket costs, whereas regulations of future uses implicate forgone profits. In fact, none of the possible explanations for the special treatment of existing uses actually justifies their protection. This Article ultimately concludes that existing uses should not be entitled to any special judicial protection but instead should be subject to the same takings and due process analysis that applies to all regulations and government actions.