HDD Health is a small tool which claims to use Self Monitoring and Reporting Technology (S.M.A.R.T.) to report on the condition of your drives.
We say "claims" because in our tests, the results were rather inconsistent. Sometimes HDD Health correctly managed to report details such as seek error, spin time, HDD temperature and so on. But on other occasions it gave significantly different figures to other programs, and there's good reason to believe that HDD Health was the tool in error (it reported the temperature of one drive as just below freezing, for instance).
This is a pity, because HDD Health does provide a lot of information and options. You're able to view your drive manufacturer, model, firmware version and capacity at a glance, for instance; all kinds of low-level extended information is available at a click; and the program can alert you to both drive health and low drive space conditions.
As HDD Health is also free for personal use, then, it might be worth installing a copy on your own system, just to see how it works for you. Take a sceptical view of its health reports initially, though, and ideally compare them with another SMART monitor to confirm that you're getting an accurate view of your system condition.