The read sweep performed on the unit of memory may conduct a read scrubbing of the data written thereto, e.g., using the current optimal threshold voltage shift values associated therewith. By performing a read sweep on the unit of memory, it may be determined if data can be read from the memory and/or whether the RBER of any subsets (pages) of the unit of memory exceeds the aforementioned threshold. Accordingly, the read sweep preferably reads back the data previously written to the unit of memory during operation 564. While reading the data written to each sub-unit of the memory (e.g., to each page of a block of non-volatile memory), the number of errors encountered are accumulated and may be stored in memory, e.g., a lookup table. Alternatively, the read sweep procedure may also include an additional calibration of the memory unit.

When the read sweep of operation 576 results in a number of read errors which exceeds a retirement error count limit, decision 578 may determine to advance method 500 to operation 508 whereby the result of the re-evaluation is to retire the unit of memory. Alternatively, if decision 578 determines that the read sweep of operation 576 was performed with adequate success (e.g., such that no read errors occurred, a number of read errors below a retirement error count limit occurred, etc.), method 500 is advanced to operation 506.