Abstract: Techniques are presented for performing maintenance operations, such as garbage collection, on non-volatile memory systems will still respecting the maximum latency, or time-out, requirements of a protocol. A safety guard band in the space available for storing host data, control data, or both, is provided. If, on an access of the memory, it is determined that the guard band space is exceeded, the system uses a recovery back to the base state by triggering and prioritising clean-up operations to re-establish all safety guard bands without breaking the timing requirements. To respect these timing requirements, the operations are split into portions and done in a phased manner during allowed latency periods.