[wccrawford]

This sounds exactly right to me. You write mocks for the things that could take too much time to run frequently with the real code. (And I'm assuming you'd also write it for things that you don't want to make actual changes somewhere, such as a third-party API that you don't control.)

But if it could be run locally, quickly, you wouldn't bother mocking it.

If that's all correct, I think you and I would do the same things. All the people screaming "no mocks!" and "mock everything!" are scary, IMO.