Yes you should learn how to backup and restore your database, content store and alfresco configuration. And you may also want to consider backing up your lucene indexes. Export and import are not really suitable for full backup purposes, since they will be far too slow, may have file size limits and can't be used incrementally.
By all means use export/import for small bits of ad-hoc backup via ftp or ACP, however that's not the way to go for your full backup.