Backing up your system greatly reduces the risks of losing valuable data. Here are some tips:
Are you using a suitable internet security/antivirus system? This should prevent malware problems, but will not help against damage or loss of hardware caused by say the building burning down, or less dramatically malicious action or theft.
If you do not have multiple versions then infected/damaged files can be backed up and that would be all that you could retrieve. Multiple backups should allow you to go back to before damage/corruption/infection started. Off site backup protects against fire etc.
You should have a plan of what to do if your system or server fails.
Best to discuss the above with your system provider.