I started smoking cigars as a New Year's resolution for 2008 and I quit smoking cigarettes three weeks ago today. Prior to quitting, for the past 15 years, I had smoked varying amounts of Marlboros--anywhere between a third of a pack a day as I was slowly weaning myself off of them over the course of 8 months, to 2-3 packs a day in college and law school.
I echo everyone's sentiment that this is a situation that differs dramatically from person to person. However, I found that by writing the date and time I opened each pack on the lid (I switched to boxes from soft packs at the start of my weening--both for an easier writing surface, and so I'd always be able to count and ration cigarettes) an also keeping track in a journal, along with total duration per pack and an "hours per cigarette" value, I'd be able to chart my progress and slowly improve. There were times when I'd be drinking like a madman and a pack would be gone in an evening, but there were also other times when I'd stretch a pack over 90 hours. The key for me was just beginning to be able to say to myself, 'instead of going out for that smoke right now, how about you go in an hour, or after you finish (whatever)' which basically gave me a little bit of preparation for dealing with the nicotine withdrawal fits when I eventually quit.
Earlier this month, I went on an annual four day camping/drinking trip up in Wisconsin. I bought a carton to take along with the intention of smoking my nuts off for that last hurrah weekend and then quitting that Monday after my return. When I got home, I realized that I had only gone through four packs. I was astounded. After having cut back my consumption for 8 months, a pack a day actually seemed like I was going nuts. In past years, I've finished off the carton on this particular trip.
I'm writing my quit date on one of the remaining unopened packs and throwing it in the back of the freezer for the rest of my life just in case I have a truly catastrophic day somewhere down the line and absolutely need a cigarette, but for all intents and purposes, that pack will cease to exist. I'll be giving the remaining five packs away in a contest here very soon.
I think I'd go so far as to say that having cigars to smoke has made quitting cigarettes a little easier for me. I don't inhale, and I rarely smoke more than one cigar a day so it's not like they're a replacement or anything, but it does seem to sort of satisfy that lingering need to engage in smoking routine behaviors. I also found Blow-Pops to be an excellent replacement for when I found myself craving a cigarette.
Good luck.