1. A method for managing returns to a host in response to read commands received by a solid-state drive (SSD) device from said host, the method comprising: receiving a data read command from said host; computing the total estimated time to completion of said read command based on an estimated time to completion for each operation submitted to a respective non-volatile memory die corresponding to said read command; wherein an estimated time to completion of said read command is based on the current performance capabilities of at least one respective non-volatile memory die as said performance capabilities change over time; determining, based on said total estimated time to completion of said read command, in what order to return requested data to said host relative to other data read commands received from said host; and returning said requested data to said host in the order determined.