MOST OF US DON'T NEED 4TB hard drives. Most of us don’t even need 3TB drives. Unless you create, edit, or store lots of high-definition video; have backups of all your machines; have a massive lossless audio library; or…. You know what? Maybe we do need 4TB drives. After a couple of years making do with puny 3TB drives (like animals!), it’s time to get 25 percent more stuff into our 3.5-inch drives.