I was one of the subjects in a government study about soldering, apparently the only concerns of the study were with regard to the possible triggering of asthma attacks in a very tiny percentage of known asthma suffers - caused by the flux vapour.
They were unable to find a single case in the service industries, but there were odd ones in manufacturing, where you soldered 8 hours a day! - their conclusion was that no extraction was required for the small amount of soldering done in a serice environment.
Presumably the same would apply to the amount of soldering done in a home environment?.
So basically, if you want to extract?, fair enough - it won't do any harm, but it won't do any good either!