A simple basic set of audit actions should be active all the time. The ideal minimum is to capture user access, use of system privileges and changes to the database schema structure. This basic set will not show attempted access to specific data that shouldn't be accessed; however, it will give a reasonably simple overview of "incorrect" access and use of privileges. If an employee is suspected of inappropriate actions or if an attack has been suspected then more detailed audit can be turned on for specific tables. From a data management point of view, auditing data changes for all tables in the database is not really practical and could also affect performance. Monitoring data change access on critical tables (such as salaries in a HR database) should be considered.