I honestly have no idea. I struggled for years after I started vaping. I started out guilting myself almost into depression over slipping. For some time I would still smoke one in the morning and then vape and use snus the rest of the day without issue. I don't remember the date but one day I just woke up and didn't want that first cigarette in the morning. It didn't help any that my wife still smokes and there was always that pack and lighter sitting in the garage. I don't blame her for my issues. At one point I was vaping, using snus, and nasal snuff along with vaping some wta. I really think it was a mental block rather than any kind of physical addiction that kept me wanting to smoke. I still use snus and vape but that is enough to keep me level now.