An invention is provided for managing non-volatile memory having a plurality of memory blocks and a plurality of error values associated with the memory blocks. The method includes recording an error value indicating a number of errors occurring in a memory block during an operation accessing the memory block. The error values can then be aggregated to calculate an overall health of the memory, or used individually, for example, by selecting a memory block for a memory operation based on the associated error value. In general, the error value is updated when the most recent number of errors occurring in the memory block during an operation accessing the memory block is greater than a current recorded value.