$$When assessing different options, relevant costs and expenses directly impacted by a particular decision should be considered. These expenses are focused on the future and vary depending on the options. Avoidable fixed costs that are unique to a certain decision might also be considered relevant costs, in addition to variable costs. For instance, fixed costs become relevant if discontinuing a product line removes related fixed costs. Since they have no bearing on the choice, irrelevant costs such as sunk costs or costs that are constant across options should be left out of incremental analysis.