An SSD metric called terabytes written (TBW) refers to the point where, after a certain amount of data being written to the drive, its cells will begin to fail, meaning the available space on the drive will shrink as the drive electronics compensate and take the failing cells offline. The TBW rating of a drive is usually anywhere between 100TBW and 3,500TBW, depending on the manufacturer, the capacity, and the use case, but for the most part this isn't a figure that will affect daily users. That said, those buying an SSD for professional applications such as filmmaking, server hosting, or anything else that involves large file transfers of the magnitude of hundreds of gigabytes daily will want to choose a drive that can withstand that kind of punishment for months, even years on end. This figure also folds into the warranty period for a drive, which (aside from a few fringe cases) will almost always be for three to five years or until you hit the TBW spec. Manufacturers have ways of reading a drive to determine how many terabytes have been written to it over its lifetime, so make sure before you submit any warranty requests that you haven't already gone over your TBW before the warranty period has expired.