From USA Carry:

Many shooters take a basic handgun training course and/or complete the fundamental concealed carry licensing or permit class and stop at that point. Sadly, I have learned that several of our beginning students have done this, even after I have encouraged them to continue their handgun training to the next level. And I am not talking about only the mechanics of shooting, like proper grip, stance, sight alignment, sight picture, trigger control, follow-through, and a few use of deadly force laws. I know I felt that I learned so much after my day-long introductory concealed carry course that I felt that I was ready to defend myself in deadly-force situations and did not need further training on the basic mechanics or other skills.