By most measures, the adoption of modeling and simulation techniques in healthcare service development falls well short of the uptake of such techniques evident in other sectors, such as business and commerce or aerospace and the military. The question is, why? To answer this, we consider three questions and then turn to the nature of answer which might lead towards greater adoption. The first is the vexed question of how good is good enough? The second concerns how best modeling should link through to decision-making; and the third concerns the culture needed to make the most of modeling and simulation (and whether it is worth the effort to make the transformation). From these, we draw an agenda for further enquiry in terms of stakeholders, their culture, data, and expectations, and the case in terms of value.