Command & Conquer 3: Tiberium Wars/Economy

Early in the game, and quite possibly later on, you are better off building two Tiberium Refineries and selling one, hence getting two Harvesters per Refinery. In addition you will need to periodically build Tiberium Silos in order to expand your cache size or your economy will be capped at a certain amount. (If you are playing as Scrin, you don't need to worry about that.)