Preparing for a test and field usage for the everyday application is two distinctly different subjects.
Lets take test prep first.
The NEC is a "code" book, and when one signs up to take a test, code is only part of the test. There usually are instructions that explain what percent of the test involves code, general knowledge, business law, etc...
It is up to the test taker to prepare oneself for the test, not for the test provider to prepare the test taker. Knowing there will be other information that is required on the test is a help. My experience from 4 years of test prep is 90% of the individuals who are preparing for a test have not opened any book (including the NEC) for any consistancy, for years... some not at all if they did not have a formal apprenticeship. These are the ones who usually complain the most about the test. Then they expect a class to solve all of those problems.
In our area, the applicant has to prove 11 1/2 years in the field in order to apply for the test (I know that is a lot, I agree). In that time a lot should have been learned... yet they may have "skated" for years not realizing that in a few years they may want to or have to take a test.
For these people, I say you have a difficult road ahead of you in preparation for a test. Don't complain, it is wasted energy...put that energy into the prep for the test, take classes, open the different books you need to and work hard. The benefit of passing a license test are endless: freedom to control your future, prestige, potentially tons of money, being able to help others, it goes on and on.
Buckle down, study (for some that may take many months), give up your free time to help yours and your family's future.
For those who are in the field.
Add to your code book whatever you need, there is no law against it. You should see my code book. I have tons of stuff added to it.
To all, I say
GOOD LUCK!!!