I used to be a smoker. I just kept on making myself busy with different things like gaming and work. I just woke up one day that I don't like smoking anymore.
I hope it was easy to quit just like that. It really depends on the smoker I remember the saying "if there's a will, there's a way".
That is a really long period of time. Did you try vaping? You can regulate the amount of nicotine in it.
Vape is a good alternative. My cousin switch to vaping and he is using an e-juice with less (or nothing at all) nicotine. Now I can see him vaping rarely and not smoking too.