Joan owns a print shop and has a difficult time figuring out what to bid on jobs. She knows how to estimate the cost of materials and labor on different jobs but is confused about how to handle many other costs she knows she incurs to run the shop. These include utilities, cleaning staff, property taxes on the building, and other expenses. Many of these types of costs vary from month to month. In addition, she often does not know the amounts until some time after jobs are completed.

Write a memo to Joan explaining how she should apply her overhead costs in developing bids on her jobs.