Somewhere in the annals of cks's blog is a discussion of why it's a good idea to document things you don't do.

We all instinctively know that we should document why we do things that we've done, especially when the rationale was intricate, cost money/time/effort, or there's a business-critical reason for it. But what about the things we don't do?

We can spend a lot of time/money/effort contemplating an action, discussing it and weighing the options, and then at the end of the day/week, we decide that it's better not to do it at all. Shouldn't we document that decision process as well? Won't it save time in the future when someone gets the same bright idea?