Smoked from 12 to 26 (and 32 to 33 - not even one man, it's enough to restart.) Not the longest I know, but when I quit, I had for half my life. My trick was wearing the patch for about a week, (2 patches actually, figured one per daily pack) to get myself simply used to not putting a cigarette to my mouth constantly. Then I just took them off and white knuckled the next 3-4 days.
Hardest thing I've ever done, honestly. The worst part was the circular thinking, always back to it. I'd try and think of anything but smoking, and my this would instantly go meta about how I was trying not to think about smoking, and right back to smoking.
They still occasionally look good to this day, ten years later, but not having to go back to that feeling of dependence and need makes it worth not picking up again every time.