Q: What is vintage status?

Yesterday, I had a conversation with a Genius bar tech, and she told me that my computer may be entering "vintage status" soon and I may want to consider replacing the hard drive.  I have a Mac (21.5-inch, Mid 2010).... Can you define what "vintage status" means?  I personally do not like to replace things simply because they are getting "old".  They ran a number of hardware tests and they all came out as OK / Passed.