You should always backup your libraries on a regular basis. The Developer's Assistant will remind you to perform a backup when one has not been completed after several uses. But you can perform a backup any time by using the Backup option from the File menu. Or you can click the Library Toolbar backup button. Then accept the default backup file name and location or select a different backup location. Click "Next" to begin backing up your Libraries. When the backup operation has successfully completed click the "Finish" button.