HD Tune is a hard disk analyzer that offers a wealth of information about the internal hard drives that are connected to the computer. It does display general information like the type of the hard drive, the serial number, capacity, firmware version and buffer size which are nice to know because it allows you to check if that hard drive is the correct one. I remember more than one instance where a friend of mine bought a hard drive only to find out that the clerk handed him one that had a lower capacity and different model number.
Far more interesting is the information about the supported and active transfer mode. If the active transfer mode does not equal the supported one you need to check on that because your hard drives are not running at top speeds then. A list of supported features of the hard drive is also shown which give you a wealth of information as well.
The temperature of the hard drive is shown in the program window as well and in the system tray so that you can react if it should rise to a level that the manufacturer deemed risky. If that is the case you need to check on the cooling system of the computer and probably add another fan to it.
Hd Tune has a separate health tab that checks several variables and displays their status. If something does not look right in this menu you should definitely consider backing up all important data and consider purchasing a new hard drive.
Two scans are available. The first is a simply benchmark that tests the read and write speed of the drive while the second is an error scan that lets you know if sectors on the hard drive are damaged.
I would not run HD Tune all the time but every now and then to check on the hard drives. It's a good feeling to know that everything is alright.