The Capability Maturity Model Integration (CMMI®) expands best practices from the software-only realm to include system engineering and other disciplines. It has significant requirements for estimating and tracking project’s effort, cost, and other parameters. Many of the specific practices in the project planning and project monitoring and control process areas were derived from a paper (Kile, 1986) published in the mid 1980s by the author. The paper described an eight-phase estimating process that was solely intended for software estimating. The concepts have evolved over the years to include estimating systems consisting of hardware, software, and services. This paper will cover the CMMI requirements for estimating and show how the estimating process has evolved to include hardware and systems. A unique demonstration of the concepts will be presented using the public-domain REVIC software cost model. A threaded scenario will be presented and the audience will have a chance to influence the demonstration and results. The demonstration will show use of a cost model during feasibility, proposal, and ongoing project phases. A small version of this interactive demonstration has been used in estimating training for over 15 years and never fails to amaze people with how cost models can help project managers throughout the project.