Gave up a two pack a day habit many years ago, cold turkey. I came to realise that smoking is quite literally a habit. Think about the times you "automatically" smoke: get a cup of coffee, light a cigarette; start to talk on the phone, light a cigarette; finish a meal, light a cigarette; have a drink, light a cigarette, and so on. By becoming more aware of the interactions caused by habit, it is easier to break the cycles. It is sort of like asking yourself "Why am I really doing this?" and realising there is no real good or logical reason. I hope this helps...
