A question on charting.

I am trying to prepare for the documentation part of my next test and I have a general question as far as how I should approach studying for it.

Would you think the questions would be phrased something like

"Patient has (blah blah blah), which charting method would be most appropriate to use".

or

"Which kind of charting would be used if only significant findings to standards are charted".

I have a feeling in real life we chart by whatever system the hospital wants us to use, but in the case of nursing questions on a test is it nec. for me to know which charting system I would use in a case by case type of deal?

So I guess what my question is, is it enough for me to know what the charting systems are and how they are used, or do I need to know which one should be used in any given situation?

As I said, I have a feeling that we have very little, if any, input on what format of charting we do in real life, so I am not sure if learning 'when to use' is nec.; given hospital policy I would think makes those decisions.