Actually, backing up important data is a must. But sometimes people ignore this rule and get into trouble in case of computer crash, or when some malware deleted files or even formatted the disk.
Using data recovery software can help to solve such problem. Usually, data recovery program scans the entire hard disk drive surface and rebuilds all the system data: from partitions and logical drives, to files and folder structure.
So, the only really reliable method to keep your important data safe is to make backup copies of it periodically. Don't forget to do this!