It is always best to ensure your data and systems are securely backed up. But if the worst happens, and your drive fails, with no backup, having a professional data recovery provider is essential. We have 30 years of data recovery experience, and we have specialist systems to read from drives that have failed. It is CRITICAL that the drive, once failed, is treated with utmost caution. As well as ensuring no physical knocks, drive access must be kept to a minimum. Running a fix utility or disk checker can quickly damage the drive beyond recovery - sadly the most common cause for our recovery to fail is because somebody else ran utilities before it came to us. If a drive has been opened (the cover has been removed) then this generally prevents and data recovery - never, ever do this. Where we are first to see a failed drive out success rate is very high.

Hard drive heads float on a cushion of air above the spinning platter - just a very small fraction of a millimetre. Should the head contact the platter, maybe due to a knock, drop or minute dust particle, both the head and the platter can be damaged.
Sometimes damage can be due to media failure - the magnetic coding on the drive corrupts, and the data being read is rubbish.
We partner with two laboratories for when our systems cannot recovery data, or the risk is too high.
If your drive fails - albeit a hard drive, SSD, SD card or USB, just bring it in.