I see some recommendations about running a small version of the analysis first to see if it's going to work at all. I agree, and the next level up is to also estimate the value of performing the full analysis. I.e. not just whether or not it will work at all, but how much it is allowed to cost and still be useful.

You may find, for example, that each unit of uncertainty reduced costs more than the value of the corresponding uncertainty reduction. This is the point at which one needs to either find a new approach, or be content with the level of uncertainty one has.