For many reasons armed-forces around the world revert to a diverse mix of live, virtual and constructive simulation assets as their prime technology for training. As such an armed-force’s simulation capability becomes the major cost-driver in military training programs. A way this is addressed by many is the increased deployment of COTS/MOTS immersive devices and natural user-interfaces such as virtual, augmented and mixed reality. Another envisioned way to deal with this increased simulation costs is the M&S as a Service paradigm. However, most armed forces still struggle to gain a better insight and grip on the life-cycle costs and benefits of their training & simulation capabilities. Returning questions are:  what is the best value portfolio of simulation assets/services for our investments, and how to make the training & simulation capability highly sustainable, robust and agile. Currently, the Netherlands Airspace Centre NLR is developing the foundations for a rationalization and valuation methodology to support the Netherlands Air-Force and Swiss Armed-Forces in their needs to evolve and manage their future training & simulation capabilities in the most cost-effective manner. The methodology builds on an enterprise architecture approach to align the training & simulation capability with armed forces operational (readiness) and business (cost) goals. It uses a so-called corporate training needs analysis to gain insight in the present and future situation. A valuation framework is deployed that assesses the simulation assets/services and underlying simulation capability infrastructure, resources and organisation in three key areas: training value, technical quality and cost. The latter two are rooted in a simulation capability maturity and life-cycle cost estimate model respectively, though basic and rudimentary at present state. Datafication and digitization of training processes are chosen as the manner to mature these models and manage the future training & simulation capability. Initial lessons-learned from case-studies are presented in the