For structures with slow-growing cracks, a suitable maintenance programme can be performed to avoid the occurrence of safety and/or functional problems. An economical maintenance programme is desired and the maintenance economy can be characterized by the so-called economic life. The occurrence of widespread damage in a structure which is uneconomical to repair and, if not repaired, could cause functional problems, was used to define qualitatively the economic life of the structure. In this paper, by using a quantitative economic life criterion, and taking into account the stochastic crack growth, a general formula for determining the economic life is derived, and a numerical example is given. The effects of economic repair limit, the detectability and the initial fatigue quality on the economic life are discussed.