depends on the consumption of each plant and the size of the pot. the best way to control it I think is by the weight of the pot. when the substrate is dry it becomes very light, try to orient yourself like this and you never have a problem with it again
Couldn't agree more to Darkwarsongs, since I changed watering to this setup, I never had troubles with over-, underwatering.
Good luck and big Harvests..
The correct answer is unfortunately.. The amount of water it needs. It's best with dirt to lift the pot and get a feel for what it feels like full. Then a few days lift again when you knows it's dry. Now you have a base line.. The water needs increase as the plant ages. I hope this helps and happy growing.