What it all comes down to, little guy, is a sum of many parts.
Firstly, sometimes things are asked a while back and it’s difficult to choose a cut off point. “Before so many days, you should have looked for the question first.”
Sometimes somepony might just legitimately miss that a question was already answered, even recently. No pony is perfect.
That leads into the subject of content. If it’s an important question, should it take precedent over something like a joke?
Which also leads into jokes. Sometimes a repeated question is done as a joke; just to see the response.
In the end, I just answer what I get. I don’t want any pony to fee left out!