Honestly, I've quit and started over again so many times, its not funny... But for me, the urge to quit never went away. That's why they're so addictive. Nicotine is a natural drug that triggers the pleasure center of the brain, causing it to drip serotonin into your system, thus giving you that "high" feeling, although for smokers who have smoked longer than others, that "high" goes away, and it merely handles stress. For many people, the urge takes years to go away, from what I've been told. But as I said - For me, the urge never went away, which is why I never actually quit.