Nicotine clears out of your system pretty quickly. The physical cravings subside in as little as one week, two at the most.
OTOH, the emotional / mental addiction to the habit last a lot longer.
I quit the day I went to the cardiac cath lab in a helicopter. The week I spent in the hospital was not that difficult thanks to chantix. My first week at home was not so bad, as I never smoked in the house or in front of my wife.

The worst was when I was out on my own, driving, at work, leaving the convenience store, walking out the door at the office, etc. All the trigger spots where I used to light up in the past. My hands needed something to do.
That was the hardest fOr me