Complex systems have reached the point where reuse is the norm rather than the exception. In an effort to address increasing complexity while maintaining manageability, systems engineers frequently leverage (or reuse) previously developed systems engineering products (i.e. requirements, test plans, interfaces, etc.) as a means of reducing development schedule, system cost, or risk; however, the effects of reuse have historically been difficult to quantify, and therefore justify. The second version of the Constructive Systems Engineering Cost Model (COSYSMO 2.0) addresses this need by providing systems engineers with a tool that enables the quantification and rationalization of the effect of reuse. The model has broad usability for and direct applicability to practitioners, and has been validated by both subject matter expert opinion and across over forty large and diversified systems engineering projects.