I was one of those die hard pot heads a few years ago. I smoked every day and thought i was on top of my game.
I started dating a girl who dident smoke and basically convinced me too stop (which i always said i would never do) for the first two weeks i was a asshole and all my problems seemed so horrible. But to be real straight up with you after those two weeks i felt like my mind was so much clearer and i since then have been ten times more focused on my work.
So in my experience Stopping worked for me now i dont even like the feeling it gives me when i do (which would be maybe 6 times in the last 3 years) Thats just the way it worked for me .
hope this helps you.