A whiteboard is a great tool to quickly iterate towards a shared understanding of the design at that point in time. But if you take a photo of it and think you

A whiteboard is a great tool to quickly iterate towards a shared understanding of the design at that point in time. But if you take a photo of it and think you're done with documenting your design, you A) lose most of the context of the decisions that were made to arrive at that design. And B) have ensured that your documentation will get outdated and become useless pretty soon. You've basically decided not to have design documentation but filled yourself into believing that you do. If you are serious about documenting software design to help future developers understand the system, you really do need those diagrams in a digital, easily updateable format and with textual explanations of the underlying decisions. And if doing that seems more work than it's worth, do it anyway, just with less details.