Relevant costs are best known as avoidable cost. This is used to get rid of data that is not necessary to the decision making process. This all depends on what is needed to improve the company. This does not only include variable costs, it also includes fixed costs. This decision can range from shutting down a unit or buying extra parts. Relevant costs are used more for a cost effective method rather an expense that has already been made like sunk costs. For example, needing to make the decision of taking in another order or not. If you have taken enough orders for a mattress store for the week and someone tries to place a mattress order you need to think about the time and materials it will take to build a mattress. There is a limit of how many a store can make per month because it can get busy especially if it is a small family store. Needing to order supplies last minute can be difficult and costly$.$