Thunderbird allows you to import and export calendar entries. This works well but you should be able to export and import, to files, your account settings and mail message filters. This would allow you to use thunderbird on different devices as well as have a backup in case thunderbird had a major problem with an update. This has happened to me. I updated thunderbird with a new version and it would not start up again. Any software can fail, so having ways to backup your key settings is necessary.