A multi-layer memory and method for operation is disclosed. The memory includes an interface, at least one flash memory die having a plurality of layers and a controller. The controller is configured to select an appropriate one of a predetermined number of program cycles for programming a fixed amount of host data, and for carrying out maintenance operations in one or more of the layers sufficient to permit a next host data write operation. The controller calculates an interleave ratio of maintenance operations to host data programming operations in each of the layers used in the determined programming cycle so that creation of free space is interspersed with host data writes in a steady manner during execution of the determined programming cycle.