Sometimes it is not the real bad sectors. It is the controller of the hdd which screwed up or the OS. I’ve repaired at least 2 hdds which have caused data losses last time due to reported bad sectors. I’ve used hdd Sentinel to fix it and still using the hdds. The health may drop abit like 90% but still very useable. I would say use at your own risk. I’ve no idea about the hdd regenerator. For HDD Sentinel it will do a very low level format and refresh writing and reading several times to make sure the sectors are good. So after repaired, I trust it is good to use. You can read more at the Sentinel website