It is very strongly recommended to set up backups of your store database.
If your database type is Internal (the default), go to Settings → Databases → Database Backup and set up automatic backups to a separate location, such as a USB drive or a network folder. A backup only protects you if it's on a different device from the computer running PostalPoint. Each backup also saves a .json file with all of your PostalPoint settings.
To restore your database to a computer after a disaster (or when moving to a new PC), install PostalPoint on the new computer. Then open your backup under Settings → Databases → Internal Database Restore, and restore your settings under Settings → Advanced → Load Settings from File.
Customer accounts are also saved in PostalPoint's cloud automatically and will come back on their own. You can force a full customer resync from Settings → Advanced → Sync Customers With Cloud.