Typically my strategy is: 1) Make types explicit (or generic) at any interface boundary 2) Periodically query the inferred types of things from my editor just

Typically my strategy is: 1) Make types explicit (or generic) at any interface boundary 2) Periodically query the inferred types of things from my editor just to make sure they come out to what I expect 3) If an error message feels like it's in the wrong place or an inferred type isn't what it should be, progressively make things more explicit until the problem is resolved But you're right, that's all very subjective and dependent on learned norms.