When your database activity is low, you should run a database consistency check (DBCC), particularly with a large database. Although it takes some time, it is important to determine that your SQL database is functioning well.

 A DBCC tests the physical and logical consistency of a database. When you enable the Database Consistency Check option for a backup, it performs the following tests:

• DBCC CHECKDB¡ªChecks the allocation and structural integrity of all objects in the specified database. By default, the CHECKDB performs a check for indexes that can increase the overall execution time.
  Note: The system table indexes are checked regardless of whether you select this option.

• DBCC CHECKCATALOG¡ªChecks for consistency in and between system tables in the specified database.