Diligence Is Mostly Listening
Due diligence produces documents, but its substance is conversation. Customers, former colleagues and the founders themselves will say most of what needs to be known, provided someone is listening rather than confirming.
Listen for how setbacks are described. A team that can narrate its failures precisely is usually a team that learns from them.
The file at the end of the process matters less than the judgment formed along the way. Paper protects; conversation informs.