A: It is vital to back up all of your data in case the original becomes damaged, corrupt, or deleted. To protect your data you must have AT LEAST one local and one remote backup.
A local backup is typically saved to an external hard disk drive or flash drive. You will need a drive with at least four times the capacity of the data to be backed up. This is to allow for growth as your files are edited and additional files are created. The drive needs to be encrypted. This can be done with Time Machine or Disk Utility (macOS), or Bitlocker (Windows).
The remote backup can be a drive like the local backup, but stored off-site. In many cases a better alternative is to use online backup. This can be done with Google Drive, Microsoft OneDrive, or one of the dozens of commercial internet backup tools.