In January 2003, some researchers at MIT bought 158 used, random disk drives from an online store and found that 60% of them had data still intact. Additionally, these same researchers found 5,000 credit card numbers on these disks.
When you decommission a system, you have to do something about the data on that system. It’s not a good idea to just power it down and give it away or sell it on eBay. You need to ensure that all sensitive data cannot be accessed.
It is rare for organizations and companies not to have sensitive information on their hard disks.