Provided are techniques for spare device management. Candidate devices are sorted into spare coverage groups by type. One or more candidate devices having closest fitting characteristics of a desired type are identified from the spare coverage groups. The identified one or more candidate devices are assigned to be spare devices for the spare coverage group. It is determined whether a desired number of spare devices have been assigned to the spare coverage group. In response to determining that the desired number of spare devices have not been assigned, a spare device having the closest fitting characteristics for every predetermined number of candidate devices having the closest fitting characteristics is assigned, until the desired number of spare devices having the closest fitting characteristics are assigned.