You the consumer might not feel the need to rewrite, but the drive itself has to do this periodically as a matter of internal Flash maintenance. Even Read Disturb (think ram RowHammer) is a thing for NAND. Then you have MLC/TLC technology in conjunction with modern small geometries leading to faster leakage (data persistence) and you end up with failures like Samsung 840 slowing down to a crawl, or older driver forgetting all data after being unplugged for a while, leading to Samsung 840 firmware update forcing the drive to rewrite itself periodically in the background. https://www.techspot.com/news/60362-samsung-fix-slow-840-evo...
