All digital storage devices, especially hard disk and solid state drives, should be monitored and tested periodically. While HDDs and SSDs are perceived as reliable, the truth is occasionally they are not. This is the case as result of drive manufacturers' inability to replicate all of the possible circumstances a drive may be exposed to. Often HDD, SSD and flash drive manufacturers partner with third-party designers and suppliers to source various hardware and software components, further increasing the range of potential problems. As result, periodical drive reliability testing is critical. Quite often, Data Recovery Guru engineers consult with customers who consistently fail to perform any testing. Sadly, when the drives fail, it comes as a surprise. As part of the evaluation process performed by our engineers, testing a hard drive's reliability is a required step in order to determine its stability factor. A healthy hard drive test will show a consistent graphic line throughout the duration of the test. On the other hand, a faulty hard drive will exhibit spikes in the very same graphic, possible delayed responses and even complete freezing. Take away point? Attempt to implement a reliability testing routine on your devices so unpleasant failures don't creep in by surprise. 

Bonus: While the engineers at Data Recovery Guru use advanced hardware based data recovery testing equipment, a few free software products that are feasible for light hard drive reliability testing and SMART attributes reading are:

HDDScan  found at www.hddscan.com

MHDD found at www.hddguru.com/software/2005.10.02-MHDD

HDTune found at www.hdtune.com

S.M.A.R.T. Reference: https://en.wikipedia.org/wiki/S.M.A.R.T.