For example, the UnityAnswers FAQ:
Don't write things that will be irrelevant in a few days.
This is in response to Doom 3 Codebase release details?
I was going to comment it with a link from our GameDev FAQ, until I looked at the FAQ, and realized it doesn't say anything about time restrictions. Now, it's possible the Doom Question won't become irrelevant, as it would at least have a link to the actual code.
But in general, is it a good idea to avoid time-dependent Questions, and/or should the FAQ be updated?