This IEEE article from 5/4/18 discusses a new technique that can be used to tell how old flash memory is. This is important because it gives Engineering and Manufacturing a method to identify substandard components even before they go out on product to the field.
Device counterfeiting is an ongoing concern for electronic products. Even if you are ordinarily buying components from an authorized distributor, things sometimes still go wrong due to lead time and sourcing pressures.
If you are building an electronic product that requires new flash, but inadvertently receive a batch of used flash (recycled but sold as new), your product quality may be adversely affected. Your design may require a high level of MTBF (mean time between failures), but recycled used flash could decrease your product’s life span and reduce MTBF.
For a company concerned about unintended builds with used flash devices, using the article’s discussed erase-time method during the manufacturing test process could identify such substandard flash, allowing it to be identified and sequestered, preventing future quality issues due to prematurely failing flash.