Here's what worked for me:

Peter told me "smoke and don't feel guilty."  Followed this path for another year, year and a half.

Peter again said this quip, "I noticed that when I wanted a smoke, if I lit up, the desire to smoke went away.  But the I discovered that when I wanted a smoke and didn't light up, the desire to smoke went away."

Finally, one Memorial Day weekend, many years ago a friend claimed he was quitting so I chimed in, "OK. I'm in." My mind tried to tell me, "If you don't smoke, you're gonna die." Ok, I thought, I'll die then.

Phase I, physical addiction, lasted about 3-7 days.  Phase II, behavioral addiction, lasted around 6 months to a year.  Phase III continues 35+ years later.

It's not easy, but it is possible.