For example, If the DWPD value is 0.25, the drive is 1TB, and the warranty is for four years then you can expect to be able to write at least 365TB to the drive before it starts to fail.
DWPD is a measure of how many times you could write data to the entire disk a day, for its entire warranty period. SSD lifespan is generally expressed in one of two formats, DWPD or TBW, which are short for Drive Writes Per Day or Total Bytes Written. The extra capacity isn’t directly available to the user but is instead used by the SSD controller to assist in managing wear levelling, swapping out overly worn sectors. Related to wear levelling, over-provisioning is where SSD manufacturers include more flash memory than necessary for the capacity.
For example, wear levelling carefully manages where on the disk data is written to, preventing any specific sector from wearing out too quickly. There are a number of tricks that SSD manufacturers use to minimize the effect.
