IDIQ contracts are most often used for on-call service contracts, Architect-Engineering (A-E) services, and job order contracting. Awards are usually for a specified number of base years with renewal options for additional years. These contracts typically do not exceed a total of five years in duration. The government places delivery orders (for supplies) or task orders (for services) against a basic contract for individual requirements. Minimum and maximum quantity limits are specified in the basic contract as either number of units (for supplies) or as dollar values (for services). The government uses an IDIQ contract when it cannot predetermine, above a specified minimum, the precise quantities of supplies or services that it will require during the contract period. Exact dollar amounts for minimums must also be named.