Reasons for Drive Failure
The reasons for drive failure vary from a simple bad connection (which is easily recoverable) to damage to the media itself, which could still be recoverable, but much less frequently.
If the damage occurred to the drive's electronics, the problem can be most likely fixed.
If the damage occurred to the system areas of the disk, leaving the data zone intact, the data could be theoretically recovered by a professional.
But, if the data zone itself is damaged, one can only rely on the backup.
There are two major reasons for early and sudden failure of your data storage device: poor handling and manufacturing defects.