Better have a plan to reduce technical and programmatic uncertainty (both of which have aleatory and epistemic behaviours respectively) at a planned rate, for a planned cost, on a planned time.
Or plan on being late, over budget, and reduced probability of technical success, before you start.All Value is Cost and Time dependent. Knowing the probabilistic behaviours of all three of these random variables - Value, Time needed to produce the Value, and Cost to produce the Value is required for any decision to be made in the presence of uncertainty.
This is called Software Engineering Economics