my car runs great right now, but i figure it couldnt hurt to clean things every once in awhile

so i'll probably end up doing this, this weekend. Now im going to ask a really dumb question, I see everyone using " N/A " what 'exactly' does that mean, i kinda figured it meant non turbo, by the way everyone uses it, does it mean like Turbo: not applicable? and do you think there is a harm to do this process if there is nothing wrong with the car... kinda like that saying dont fix something that is not broken?