1) Backing up data involves saving important files, folders, and system settings to another storage location to protect against data loss from hardware failures, malware, or user errors. 2) Common backup methods include disk cloning, file backups to external drives or cloud storage, and system restore points. Individual files, folders, disks, and removable drives can all be backed up. 3) Backing up is especially important before installing new software or updates, if hardware issues are anticipated, and when using devices in situations where data loss is possible, such as traveling.