If you at least read the data from the drive from time to time, the controller will "refresh" the charge by effectively re-writing data that can't be read witho

If you at least read the data from the drive from time to time, the controller will "refresh" the charge by effectively re-writing data that can't be read without errors. Controllers will also tolerate and correct _some_ bit flips on the fly, topping up cells, or re-mapping bad pages. Think of it as ZFS scrub, basically, except you never see most of the errors.