My 2 cents.
Each type of resources has their own pros and cons:
Food:
PRO - cheapest, fastest to build up in terms of rural area
CON - least influence (1000)/money tribute books (1).
Lumber:
PRO - for the price of food, 0.08-0.12 each, you get most influence (1500) and more money tribute books (2).
CON - kinda like the most important resource in early game.
Stone:
PRO - i never like to turn in stones, unless i've got surplus. probably its good coz its of the lesser importance as compared to other types in late games.
CON - a lot needed for early game to build up walls/beacon towers etc.
Iron:
PRO - for the same square in rural area, you can choose to build any type. in the end you get the same amount produced, so why not go for iron that gives the most influence?
CON - it takes the longest time to build up iron mines.
Side Note:
1) in terms of market price and influence, turning in lumbers yield the most influence per lumber, the rests are the same.
2) I dont do epic quests anymore. I find that I can make better use of my resources. But Epics can be good that you can get rewards from the emperor (equipments) if you accumulated lots of books/tokens etc.
Well,
I'm lazy so i dont collect tokens for better equipments. XD
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IGN Smexy