This will lead them to set reasonable prices which will increase the company's revenues as opposed to high prices which will discourage sales volumes and thus lead to losses. It is also important for them to know the nature of the costs they incur (whether fixed costs, variable costs, semi-variable or semi-fixed costs) and how they react to different levels of activity. This will help managers control and maintain production costs. The relevance of costs and revenues is also important for managers. They need to know which costs are relevant so they can take them into account in decision making and planning. Irrelevant costs are not taken into account in the decision making process as they have no impact on decisions. An example of an irrelevant cost is sunk costs, while examples of relevant costs are marginal and opportunity costs.