Frequency of exceedance any peak exceeding is . Its complement, is the probability of exceedance, the probability that has been exceeded at least once by time . This probability can be useful to estimate whether an extreme event will occur during a specified time period, such as the lifespan of a structure or the duration of an operation. If is small, for example for the frequency of a rare event occurring in a short time period, then Under this assumption, the frequency of exceedance is equal to the probability of exceedance per unit time, , and the probability of exceedance can be computed
Material input per service unit (MI) of the product can be reduced or amount of service units (S) can be increased. Material input in the production phase can be reduced by using less energy or raw materials. Also transport chains can be rationalized. In the use phase the material input per unit of service can be reduced when amount of service produced is increased. For instance in case of a newspaper the material input can be reduced by using recycled paper instead of primary. Material input per reader decreases when the same paper is shared with several persons. High quality products and availability of spares