Although there's not a definite answer to how long a disk drive lasts, you can expect your hard drive to survive for at least 3 to 5 years. In a study contacted by Backblaze with more than 25000 disk drives, it was observed that about 80% of the drives were still operating after 4 years. After 3 years though, they have noticed that the failure rate of the disk drives increased significally.
Note: The drives tested reside in a controled environment and thus don't face several challenges other disks face (e.g. disks on a laptop), which could contribute in a reduced lifespan.HDD, Storage Device