scope

Not depth, which is where most people push and where the returns flatten. What changes is the size of the problem you are handed, how ambiguous it is when you get it, and whether things happen because you asked rather than because you built them.

A confident plan built before you know anything is the failure mode, and so is refusing to answer until you have looked. The structure that handles both: a dated shape with the decision points named, one committed win, and the conditions that would change everything after day 30.