When you decide to quit smoking for good and put down that last cigarette it can take up to 3 months to fully stop craving cigarettes.
Using something such as Chantix or other quit smoking patches such as Nicoderm CQ Nicotine patches can help stop your cravings for the nicotine and help you stop smoking.
You might still have some cravings after the 3 months but after 6 months of being cigarette and smoke free you should no longer have the cravings for nicotine and should not have to use the nicotine patches or Chantix anymore to curb your cravings for nicotine.