At great length.
For me, the following is the transition that defined what separated Schwartz's comics from anybody else's.
To the left is Detective #326, the last issue edited by Jack Schiff. It was Batman's 300th appearance in Detective Comics, though no mention of this landmark is made. It is fairly typical of the run over the preceding ten years: Situations that wouldn't have been out of place in the Superman comics of the time, and some of the wonkiest aliens you could hope to see. If memory serves me, illustrated by Sheldon Moldoff (whose own rarely-seen style, when he wasn't ghosting Bob Kane, wasn't half bad).
To the right is Detective #327, the next month's issue, and the first edited by Julius Schwartz. As you can see, about the only thing that stayed the same was the presence of Batman and Robin. Illustrated by Carmine Infantino, making no attempt to imitate Kane.