1. A method for execution by one or more processing modules of one or more computing devices of a dispersed storage network (DSN), the method comprises: determining that a set of storage units of the DSN will be substantially used for read operations of dispersed storage error encoded data; and for the set of storage units: determining an actual reliability that indicates a level of reliability in retrieving a decode threshold number of encoded data slices per read request of a plurality of read requests; comparing the actual reliability to a desired reliability of the set of storage units, wherein the desired reliability indicates a desired level of reliability in retrieving the decode threshold number of encoded data slices per read request of the plurality of read requests; and when the actual reliability exceeds the desired reliability by a reconfiguration threshold, removing one or more storage units from the set of storage units.