Do you run on coffee, need it to function?

Just every so often, when the mood strikes? Never?
I didn't used to be a big coffee drinker but I've steadily increased my consumption over the last couple of years. I average about 2 or 3 cups a day, most days. Two cups in the morning before breakfast, then another small glass of iced coffee after dinner (it helps my sweets craving in the evening).