According to the online backup service who has been tracking failure rates, 80% of hard drives last 4 years. These stats are based on consumer based hard drives. The online backup service analyzed 25,000 hard drives it’s kept consistently spinning over the last four years, noting when each drive failed. There are a percentage of drives that go bad before the first year of use. Changing hard drives in the shop here has made me see the value of online back ups. If you’re not using some type of back up service now is the time to start.
info from http://www.extremetech.com/computing/170748-how-long-do-hard-drives-actually-live-for