The "recurring quest" trick is overrated and nowhere near practical! -- I did the
math only AFTER overhauling my city. And it won't work! Some people say that with this trick you don't need any goods buildings in the city. I now have 28 Alchemists spread across the entire land. But 14 random rewards from "saltpeter 2 times" 14 times a day, multiplied by the empirical percentage provided by reliable sources, is equivalent to having only 1 (one, ☝) goods building in the entire city. I used to have 4 (
) goods buildings! All gone now, along with the houses, because Alchemists need much fewer population than goods manufacturers.
Summary: recurring quest exploitation -- no good! (pun)