It takes longer than 3 days for your body to rid itself of nicotine, but no matter how much you smoked, it should all be out of your system in 30 days or less. For the average pack-a-day smoker, I thought it was typically 10 days to two weeks. That said, do NOT underestimate the power of psychological withdrawals symptoms. Those can last for months or years after your last smoke and can be very insidious. I quit back in 1989... like Mark Twain, I found it very easy to quit because I had done it so many times in the past. For me, the most difficult part of quitting smoking was staying quit... and combining that with the notion that it's that first smoke that gets you back to being a smoker. That's right... all it really takes is one cig, and I found, inevitably, I was on a sinking ship as far as staying a nonsmoker was concerned. Only once I resolved that even one really was too much, and stuck to it, was I able to really stay quit. And I STILL would like to have just one more, and that's 23 years later! One thing I found really helpful was to incorporate some exercise when quitting. I have heard lots of people say the same thing... get some exercise, especially cardiovasular type exercise, and that can really help with the cravings. Is this your first shot at quitting?Good luck.