What factors can cause the controls that have been established and implemented for a prolonged period to lose their effectiveness?

Being overconfident, or complacent, may result in a lack of attention to the proper procedures. Controls are most effective when strictly applied, assuming that they may become critically necessary at any time.

In addition, established controls should be evaluated if not quarterly, at least every year or be considered in terms of their related output. Some controls may not be applicable after a certain period of time. This also goes with computer software programs, too. Whether the control is machine-implemented or implemented by a supervisor, it must undergo evaluation.