Workers are used in the construction and upgrade of a player's mall. All players start with 2 of them.
At least one worker must be available in order to construct or upgrade Buildings. If there are no workers left, the player can choose between waiting for at least one construction project to complete, rushing the last construction project or buying additional workers (both of those options cost Diamonds).
Extra workers have a base cost of 250 Diamonds; subsequent extra workers cost 250 more each time.