I never accept the Pawn. First of all I never wanted to take the time to study any defenses to the KG and secondly, declining the gambit with 2...Bc5 is pretty easy to play. Developing is mostly common sense and not much can go wrong for Black. Another reason is that most King's Gambit players never bother to study lines where Black declines the gambit, so they don’t know much about those variations themselves. I’ve never bothered with declining it using the Falkbeer Counter Gambit because it looks to me like like one of those defenses where you have to know what you are doing. I’m pretty lazy when it comes to studying openings.
In the following game, when my opponent committed a positional error in advancing 13.f5, I misjudged the position by thinking I was in no danger of being subjected to a K-side attack and would have good chances of using the open g-file to attack the White King. The result was I tried to get too fancy. It would have been better to just sit back and keep improving my position. The result was I unnecessarily gave my opponent chances. Fortunately he did not take advantage of them.