1. The identity/execution was poorly conceived: Can often be identified by measures of consumer interest, brand associations, sales.
2. The target for the identity/execution is limited: May need to change to reach a broader market.
3. The identity/execution has become out of date: Markets change such that a working position may become obsolete.
4. The identity/execution loses its edge, becomes old-fashioned.
5. The identity/execution has just become tired: Same over time may become boring to consumers, losing ability to attract attention.

Source: Professor Barbara Kahn