This "Informed Educator" examines the use of a 4-day school week as a way to reduce expenses while using limited resources most effectively. Discussion focuses on various models of 4-day week schedules, what to do during the fifth day, and how 4-day school weeks affect extracurricular activities. Detailed discussion of financial savings, student achievement, teaching practice, and stakeholder satisfaction is also included. (Lists 5 online resources.) [This "Informed Educator" is based on "RESEARCH BRIEF: A Review of the Evidence on the Four-Day School Week," by Christine Donis-Keller and David L. Silvernail, Center for Education Policy, Applied Research and Evaluation, University of Southern Maine, January 2009.]