Non-recurring engineering (NRE) - refers to the one-time cost to research, develop, design and test a new product. When budgeting for a project, NRE must be considered to analyze if a new product will be profitable. Even though a company will pay for NRE on a project only once, NRE costs can be prohibitively high and the product will need to sell well enough to produce a return on the initial investment. NRE is unlike production costs, which must be paid constantly to maintain production of a product. It is a form of fixed cost in economics terms. Once a system is designed any number of units can be manufactured without increasing NRE cost.