:
: Being that a vent simply vents air and gases and not liquid, I should not have to replace a galvanized vent for corrosion and rust correct? Or am I mistaken, in that it can fail over time?

: I am redoing my whole bathroom and trying to replace everything that is old esp. galvanized sink drain and horizontal 2 foot run of a lead pipe that is toilet drain before it ties into the vertical CI that runs straight down to basement.

: I just figure that a galvanized vent should last much longer then a galvanized drain pipe correct?? Harvey

Harvey,
The vents will have little wear and tear.
The waste portions take the beating.
Replacing the lower should be fine.
Terry Love