One more thought to add. "Amateurs train until they get it right. Professionals train until they can't get it wrong." Another version of it is that "You won't rise to the occasion, you will sink to the level of your training."

I don't have time to train to the "professional" level on everything I'd like to, that's for sure. But I am trained to the "professional" level on some things, and it helps. Knowing deep in your bones that you can handle one set of adverse circumstance may be of help if you are facing something you're not as well trained for.