Bamspeedy
CheeseBob
I haven't switched from republic to democracy in a very long time (I usually stay in Monarchy for conquest games, or I go from Monarchy-Democracy, late in the game). But the last time I did go from Republic to Democracy, I only saw something like less than a 10% increase in commerce. If you are non-religious and end up going through 6 turns of anarchy, then it would take ~60 turns to earn back all the money you lost during your anarchy (assuming you are only getting a 10% improvement in commerce going from republic-democracy). If there was/is say a 20% improvement, then it would still take ~30 turns.
But the faster workers in democracy will allow you to help speed up that recovery period, but by that time you should have much of your core cities' terrain close to fully developed anyways....
But the faster workers in democracy will allow you to help speed up that recovery period, but by that time you should have much of your core cities' terrain close to fully developed anyways....