Probably should have combined the two questions, but.
It took me a few months of preparation using the book I mentioned in your other
thread to get a good enough grip on it to feel that I could tackle the exam. This is going to vary based on how much time you can dedicate to preparation for the
test - I was preparing for mine around a few other things, including work. (On the other hand, I did fairly well on it using that method, so...)