When is this a no call?

[rainmaker]

I've been told that if there are two players on the floor, there's better be a whistle. I don't think that applies to every play but the b/c on the shot really needs a call every time, I think. The easy way to get it right is to ref the defense. Keep the ball in your vision, but concentrate on the defense. If the defender is there before the shooter leaves the floor, it's a charge. If the defense is still sliding as the shooter is floating up, it's a block. When it's easy, there's no reason to no-call it.