KIM Leadley didn't think much of her one or two-a-day big coffee fix. But when she tried to go cold turkey to stop the habit, she found herself getting headaches - excruciating headaches, the I-can't-work-think-or-function kind of headaches. Within days she had fallen off the wagon and resumed the coffee habit. "The headaches did make me think there was something to be said for caffeine addiction" and withdrawal, says the 41-year-old. She started tapering off her caffeine consumption by mixing decaffeinated and regular coffee. About six months later, she finally kicked the habit when she fell pregnant.