 If a particular block is programmed and erased repeatedly without writing to any other blocks, that block will wear out before all the other blocks — thereby prematurely ending the life of the SSD.For this reason, SSD controllers use a technique called wear leveling to distribute writes as evenly as possible across all the flash blocks in the SSD.In a perfect scenario, this would enable every block to be written to its maximum life so they all fail at the same time.