Advanced warning of impending hardware doom could one day save you tearing your hair out at losing all your important data.
If you don't perform regular backups then I'd say it was essential that you use a tool like HDD Health. The program continually monitors your PC for tell tale signs that your hard drive is about to die due to corruption or plain and simple burn out. The program sits in your system tray and monitors the performance of your hard drive at regular intervals. It continually performs minor diagnostic tests to see if anything irregular is happening. The program utilises Self Monitoring and Reporting Technology (S.M.A.R.T.) however and unless your hard drive supports this (which most modern ones do) this program won't be of much use to you. The program issues alerts in the manner of your choosing - which basically means via email, pop-up messages (which can get rather annoying), net messages or event logging. It's very light on resources although the fact that it is continually working on your hard drive means that occasionally you might expect some slow down of your PC's operations.
A great tool for anyone who does not backup regularly and is worried about the heavy use of their hard drive