well, it depends...
actually, it really depends on the amount of meticulousness (is that REALLY a word??) that you desire, and what you have to work with in the first place.
It starts from the detail you take in the initial recording levels and continues on down through the mixing, EQing, mastering processes, which ALL contribute to your levels in the mix.
Compression/limiting is one important tool, so is EQ, so is your mastering. Using meters to look and listen is recommended for mixing equivalent levels (but which CW9 is lacking!!)
Too much of any one thing is almost guaranteed to be detremental to your end result (ie...too much limiting will make it sound "squashed"), but on the otherhand, may be necessary if your recording levels are highly uneven and/or volumetrically challenged.
Like I said...it depends (on what you have to work with, and how meticulous you want to be with it)...
There are MANY resources on homerecording.com (and elsewhere) that I would recommend you to read on this subject.
sorry if I contributed to confusion, but sort of a difficult question to give a simple answer IMHO...
ub