OK guys, and this is for all of you.......
At this point, no hard disk drive manufacturer actually manufactures all of the pieces. One company makes the platters, another the spindle motor, yet another the read/write head assemblies, and so forth with several other companies making the various parts which are then assembled by Seagate, Western Digital, Hitachi, Toshiba, etc.
If there becomes a known problem with a large number of the finished products, it is usually the fault of one of those assemblies rather than the entire model line and can be as specific as the production line which manufactured it.
(This is a rare exception to what I have said, so far) In the 2007-2009 time frame, one line for Seagate's 7200.11 series used a defective firmware version at one facility which left faulty data in the "system area" (where the SMART info is saved). When the drive detected a new problem, it corrupted the system area because of the faulty data and the drive suddenly became "not ready" or had a capacity of zero megabytes. Seagate actually offered free data recovery for this problem and I probably "fixed' about a hundred of them using a specialized serial port to tell the drive to rewrite that data followed by a firmware update.
Maxtor played with "fluid dynamic bearings" in the early 21st century which, when the drive was banged, would cause the platters to wobble like a top. SMART then thought all kinds of stuff was screwing up and it, too, would corrupt the SMART data because the flying height of the heads was wrong.
The infamous Hitachi/IBM Deathstars of the late 1990's failed because some idiot decided that the place to park the heads when the drive was idle was directly over the system area which was a really bad idea.
Post 2010; though, the common thread is a failure of one of the third party assemblies. Substandard head assemblies which then write flakey data, faults in the spindle motors or its driver chip, or platters that "don't quite cut it" are far more common than a bad design.
Ironically, now, the most common cause of a drive's failure is an excessive shock, especially in laptops! Nobody seems to know that a rotating hard drive is seven times more fragile than a raw egg and even the slightest bump will damage the drive with the worst case being the shock wasn't enough to cause instant death; but, rather sneaks up on the owner during the following weeks or months.
Yes, pay very close attention to the SMART data with the key values being Reallocted Sector Count, Pending Sectors, and G-Shock events. If you catch it early enough, a sector clone of the failing drive to a replacement works 90+% of the time.