After you have created and modified the database maintenance plan, you should validate the plan by doing the following:

Validate the maintenance plan. Run each subplan and check that full backups, incremental backups, and backup reports are being created in the specified locations. You can manually run each subplan by expanding the SQL Server Agent:Jobs branch in the navigation pane and right clicking and selecting Start Job at Step... for each subplan included in the maintenance plan.

Validate the deletion of old backup files. If you set the maintenance plan to remove backup files that are more than 2 weeks old, make sure to check your backups in two weeks to ensure that old backup files are being removed. It may be helpful to set a reminder in your mail, calendar, or scheduling software so that you don’t forget to do this. If backups are not removed, it is probable that the old backup files will eventually consume all available storage space, resulting in a failure to create new backup files and even interfering with the ability of your database to grow.

Ensure that your database backup files are incorporated in your corporate tape backup plan. The maintenance plans created above merely create backups of your databases to disk, but this will not protect you if the disks on which these backups reside are destroyed, rendered unusable, etc....