In praise of the second interview
The first conversation gets you their prepared answers. The second gets you the story.
Almost everything I have written that I still like came out of a second conversation.
The first interview is a performance, and not a dishonest one — people arrive with the version of events they have told before, sanded smooth by repetition. You need it. It gives you the shape, the chronology, the names. But it is the account they have already decided on.
What changes
By the second conversation two things are different. You have done the reading, so you can ask about the thing they skipped. And they have had a week to think about what they said, which is often long enough for someone to decide they would rather be understood than protected.
The request itself signals something too. Asking to come back says the first answer was taken seriously enough to have follow-up questions, which is not how most people experience being interviewed.
The cost
It is slower, and on a fixed fee it eats the margin. I build it into the quote now rather than pretending the first conversation will be enough, because when I have skipped it the piece has always been thinner and I have always known why.