I do about the same, 3-6 cups or so. Hmm, 3-6 mugs I should specify. That's on the weekdays, I'll maybe drink one or two on the weekends. On vacation I'll go days without any, no withdrawal headaches or any other signs.

I guess that makes me able to quit at anytime I wish without suffering.

Ironically I spilled coffee on myself while typing this up. It must have thought I was threatening to quit and did a preemptive attack.