The way I've been taught is to use your hangers to get position on the next shot, or the more difficult ones, or both. Leaving my open shots in front of the pocket is an invitation for my opponent to knock them away from the pocket in his attempt to make his shots, and then I no longer have the easy shot that I once did. "Take the duck".... I hear it all the time. I listen, most of the time. If it's that easy, I should be able to use it to get position for the next ball, or to move one of my opponents balls, or both.
Yes, there are always going to be times where it's advantageous to try and block a pocket. But I still have to make mine, too. Balance. Choices. Planning. Damned difficult game, this. Plenty of fun, sorting it all out. :embarrassed2: