Abstract: In a method for estimating the failure rate .lambda.(t) of corresponding ponents in a stock of technical devices such as, for example, vehicles of all kinds, where the number of components failing within a given time interval and hence having to be replaced by repair or replacement is continually established and from this a lifetime distribution f(t) of said components is determined, it is disclosed that, in a total stock varying with time according to a specific or continually ascertained stock function G(t), the lifetime distribution f(t) or the cumulative lifetime distribution F(t) be corrected by taking the stock function G(t) into account.