A hook is necessary when you are in the 25% but it is clear that your relevant opponent has an advantage, in that it is too late for you to win a ride-off and not possible to look for a foul.
Hence the priority is to prevent a shot being completed without committing a foul. This requires a good technique that can be applied when close to and behind an opponent.

Many players frequently miss opportunities to hook in the mistaken belief that they are too far away. But if the victim if is taking a full swing for an extended right arm, you can hook from a distance of two mallet lengths. I suggest that, if you place two polo mallets end to end on the ground, you will be surprised to see how much ground is covered by them and will realize the possibilities of hooking from further away than expected.