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: obtaining estimated future availability information for storage units of the DSN; organizing a plurality of sets of encoded data slices into a plurality of group-sets of encoded data slices, wherein a group-set of encoded data slices of the plurality of group-sets of encoded data slices includes multiple sets of encoded data slices of the plurality of sets of encoded data slices, wherein data is encoded in accordance with a dispersed storage error coding function to produce the plurality of sets of encoded data slices; for each of the plurality of group-sets of encoded data slices, estimating an approximate storage completion time to produce a plurality of approximate storage completion times; obtaining a write threshold number; establishing a time-availability pattern for writing the plurality of group-sets of encoded data slices to the storage units based on the estimated future availability information, the plurality of approximate storage completion times, and the write threshold number; and sending the plurality of group-sets of encoded data slices to at least some of the storage units for storage therein in accordance with the time-availability pattern.