Managers must be prepared to modify their strategy except when:

a. changing circumstances affect performance and the desire to improve the current strategy.
b. rivals make or adjust moves in the market due to the shifting needs of buyers.
c. encountering stagnating market conditions and increasingly restrictive new customer acquisition opportunities.
d. evidence is mounting that the current strategy is becoming less effective.
e. rivals announce their monthly profit margins in public.

Strategies are the actions or plans which are put in place by a company in order to have competitive edge over its rivals and also achieve the organization objectives.

Managers must modify their strategies when:

• changing circumstances affect performance and the desire to improve the current strategy.

• rivals make or adjust moves in the market due to the shifting needs of buyers.

• encountering stagnating market conditions and increasingly restrictive new customer acquisition opportunities.

• evidence is mounting that the current strategy is becoming less effective.

The last option isn't necessary in order to modify their strategies. Rivals announcing their monthly profit margins in public isn't enough reason for a company to alter its strategies.