If your hard drive suddenly fails on you then unless you've backed up absolutely everything, then you can potentially lose everything.
GSmartControl is a graphical user interface for Smartcl which is is a tool for querying and controlling SMART (Self-Monitoring, Analysis, and Reporting Technology) data on modern hard disk drives. GSmartControl makes it easier to inspect the drive's SMART data to determine its health, as well as run various tests on it. Note that not all drives are SMART equipped but most modern drives support it. It should be noted however that in this current version, only ATA drives (both PATA and SATA) are supported.
GSmartControl is definitely preferable to using the normal SMART interface and makes it much easier to read performance stats and confirm your status. A lot of the information will be simply indecipherable jargon for the average user such as Reallocation Event Count, Spin-Up Retry Count and Offline Uncorrectable stats. In fact, just because the data is better presented, doesn't mean it's any easier to interpret.
GSmartControl offers a much more attractive stats readout for SMART drives. Just make sure you've read-up on how to interpret it all!