All NAND flash memory contained in flash storage devices degrade in their ability to reliably store bits of data with every program or erase (P/E) cycle of a NAND flash memory cell until the NAND flash can no longer reliably store data. At this point it should be removed from the user addressable storage pool and the logical address moved to a new physical address on NAND flash storage array.
As the cell is constantly programmed or erased, the BER also increases linearly and therefore a complex set of management techniques must be implemented on the enterprise SSD FSP to manage the cell capability in reliably storing data over the expected life of the SSD. 
The P/E endurance of a given NAND flash memory can vary substantially depending on the current lithography manufacturing process and type of NAND flash produced.
|NAND flash memory type
||3 bits per cell
||2 bits per cell
||2 bits per cell
||1 bit per cell
|Approx NAND Bit Error Rate (BER)
Table 2 – NAND flash memory types    
As an enterprise-class SSD must be able to withstand heavy write activity in scenarios typical for a datacentre server that requires access to the data for 24 hours of every day in the week compared to a client-class SSD which is typically only fully utilised for 8 hours each day during the week, e-MLC is the perfect match for high performance, capacity and endurance SSDs.
As an enterprise class SSD must be able to withstand heavy write activity in scenarios typical with a datacentre server requiring access to the data across the entire 24 hours of every day in the week compared to a Client class SSD which is typically only fully utilised for 8 hours a day in the week, e-MLC is the perfect match for high performance, capacity and endurance SSDs.
Understanding the write endurance of any application or SSD can be complex which is why the JEDEC committee also proposed an endurance measurement metric using the TeraBytes Written (TBW) value to indicate the amount of raw data that can be written to the SSD before the NAND flash contained in the SSD becomes an unreliable storage medium and the drive should be retired.
Using the JESD218A testing methods and JESD219 enterprise-class workloads proposed by JEDEC, it becomes an easier task to interpret an SSD manufacturer's endurance calculations via TBW and extrapolate a more understandable endurance measure that can be applied to any datacentre.
As noted in documents JESD218 and JESD219, different application class workloads can also suffer from a write amplification factor (WAF) in order of magnitude higher than the actual writes submitted by the host and easily lead to unmanageable NAND flash wear, higher NAND flash BER from excessive writes over time and slower performance from widely distributed invalid pages across the SSD. The on the fly compression mechanism utilised on the Kingston E100 with LSI® SandForce® DuraWrite™ technology reduces the overall WAF and extends the NAND flash rated endurance for applications in the enterprise class.
While TBW is an important topic for the discussion between enterprise and client-class SSDs, TBW is only a NAND flash level endurance prediction model and the Mean Time Between Failure (MTBF) should be observed as a component-level endurance and reliability prediction model based on the reliability of components used on the device. The expectations placed on an enterprise-class SSD's components include longevity and working harder at managing the voltages across all NAND flash memory over the SSD's life expectancy.
S.M.A.R.T. monitoring and reporting on enterprise class SSDs allows the device to be easily queried pre-failure for life expectancy based on the current write amplification factor and wear level. Pre-failure predictive warnings for failure events such as a loss of power, bit errors occurring from the physical interface or un-even wear distribution are often also supported.
Client class SSDs may only feature the minimum S.M.A.R.T. output for monitoring the SSD during standard use or post –failure.
Depending on the application class and capacity of the SSD, an increased reserve capacity of NAND flash memory can also be allocated as an over-provisioned (OP) spare capacity. The OP capacity is hidden from user and operating system access and can be utilised as a temporary write buffer for higher sustained performance and as a replacement of defective flash memory cells during the life-expectancy of the SSD to enhance the reliability and endurance of the SSD.