Windows Azure SQL Database billing is prorated daily. This means that if you create a database and delete it right away, you are will be billed for the full day.
I bring this up because the Windows Azure SQL Database automatic backup feature is built on top of the import/export service. To backup your database, the service follows best practices in order to create a consistent point-in-time copy of your database. Then it exports it to a bacpac file and places it in your Windows Azure Storage.
The automatic backup feature is well worth its cost of operation, but you might want to review your backup frequency. Especially if your databases are large.
So how does this show up on your bill? Well for starters, backing up every day will result in paying for your actual database and for the temporary database instance used to create the backup. Backing up every second day will costs you roughly one and a half times what it costs without backups.
If it’s so expensive, why should I consider scheduling backups? Windows Azure SQL Database is already backed up by two identical copies at all times. Why should I pay for more backups?
Well that’s exactly it, all 3 copies are identical. If a careless user decides to execute a DELETE statement or an UPDATE statement without a WHERE clause, the data gets altered in all 3 copies!
Incidentally, the 3 copies are there to deal with infrastructure failures not users. The automatic backup feature available for Windows Azure SQL Database is essential, because if something goes totally wrong, you will have a backup to work with.
Think about it, does paying for an extra database from time to time cost you more than what it would cost you if you lost everything?