In the discussion S.M.A.R.T. of attributes:

XXX is Welcome!
Here’s what my old good 640 GB Seagate hard drive shows. Purchased a long time ago, somewhere in the area 5-10 years has passed.
*Smart screen with a critically large bunch of relocks*
Should we panic? There is a lot, enough important data on it! Sometimes it "disappears" from the system, appears only after restarting the computer.

yyy: If you don’t have a backup then immediately shoot yourself in the foot to feel the pain of data loss.