"Whatever can go wrong, will go wrong."
- Murphy's Law
"Murphy was an optimist."
There's a saying in the "prepping" community, "Two is one and one is none", which means that if you rely on one item or plan to get you through the bad times, that single item will fail you at some point.
This is true in industry, communications, warfare or any other endeavor that relies on equipment or processes. Things break, people forget stuff, and Murphy's Law reigns supreme.
So how come people get their concealed carry license and think that's all the training they'll need? Or why do some people latch onto a single "style" of firearms training rather than seek out different trainers with different techniques?
I've had training from many different firearms trainers, from local NRA-approved instructors to bigger names like Rob Pincus and Gabe Saurez. I've had training in pure "combat" techniques but also have attended classes from top-notch competition shooters like Rob Leatham.
And you know what? None of what I learned in all those diverse training classes has stepped on or hurt my ability to learn other styles of training. The "balance of speed and precision" you learn in a Combat Focus Shooting class works just dandy in an IDPA match, and the quick target transitions I learned from shooting USPSA helps me be a better student in a self-defense class.
In addition to all of those benefits, consider this: If (God forbid) you are involved in a self-defense shooting and wind up needing to go to court to defend your innocence after you've defended your life, the people who have trained you how to safely and efficiently use a gun can (and probably will) be called to testify on your behalf. Think about it: Would you rather have one person take the stand in your defense, or have a half-dozen people (or more) talk about how you were trained by them to safely use your gun?
Strength in numbers is true on the street, and it's true in the courtroom as well.
So if you've had some training beyond what's required for your concealed carry permit, consider branching out to new trainers and new classes to broaden your horizons and improve your ability to deal with whatever life throws at you.