I'm a bit confused by your comment. If you play lots of one pocket, aren't you learning from your opponent by watching their moves? Wouldn't you learn more from a better player? If your opponent tells you what you might have done differently after a shot, aren't you learning from them? Learning by yourself (trial and error) can be a very slow process. Lessons from a qualified instructor can speed up the learning process dramatically. I would include learning defensive moves a part of any pool lesson. Many of my students come to me specifically to learn defensive strategy, and they seem to win a lot more after a lesson or two. My imagination?
Donny L
PBIA/ACS Instructor
Gainesville, Fl