Will smoking a few cigarettes harm dental implant?

Q. I am a smoker and have just had two implants. Bone has been grafted for a third. Despite the fact that I have been warned strongly and have read about all the danger of smoking, I find I am still sneaking one or two a day. Trying to stop completely seems impossible and I am wondering if it is possible to have a couple a day or if I am just kidding myself. The tension of it all is dreadful.