A severe surge could damage your equipment, and destroy your data. Avoid surges by using a high quality surge protector. On rare occasions, electrical power may completely go out for periods of time. If this happens while your computer is writing data, the information will probably be corrupted. If your computer is accidentally exposed to a strong magnetic device, bad things can happen.
Hard drives use magnetic storage media.
Therefore magnets will destroy the structure of all of your data if they are too close to your computer. The same is true with floppy and ZIP disks. You or someone else may accidentally delete or overwrite some important files. A malicious person may use illegal means to gain access to your computer files while you are on the internet or connected to any type of network. There are a number of choices when backing up data.