What are the odds of the Earth being hit by an asteroid from the asteroid belt?
I’m sure it happens all the time – probably more than daily. It’s mostly very small stuff. However, what we know isn’t the odds of something coming from some particular previous orbit, what we know is the frequency of strikes as a function of size. And big rocks, like the one that killed the dinosaurs, come on approximately 100 million year intervals. There is evidence that the currently named Baptistina asteroid in the main belt was disrupted some 160 million years ago, leading to the K/T event.
