One important note on keeping/loosing CPs.
If you hit mob A, gain CPs, then switch to mob B and hit mob B, you will loose all the CPs earned on mob A. If however, you switch back to mob A (after selecting mob B) without hitting mob B, then your CPs earned on mob A are still present for you to use.
Just mentioning this because it is ennoying when, in the heat of combat, you switch target accidentally and as a consequence loose all your CPs.
Some CPs you will earn later (for instance through the skill "Premeditation") need to be used within a certain time frame or they are lost.
nostra