How old does a game need to be to warrant a remake?

[Zkuq]

At least two console generations, and maybe more depending on the game. I haven't played Dead Space but my impression is that it's not in need of a remake just yet. On the other hand, someone mentioned Oblivion, and it's aged very poorly, to the point where it would benefit a lot from a remake. Going back even more for an opposing example, I don't think Doom 3 still needs a remake (although it too would benefit a bit from one).