Eisenhower picked up smoking during his time at West Point and by the end of World War II was up to smoking 4 packs a day.
In 1949 he decided to quit and began by trying to remove cigarettes and ashtrays from the spaces he occupied. When this didn’t work he went the opposite direction. He surrounded himself with temptation.
His pockets were stuffed with cigarettes and he made it a practice to offer one to every person who came into his office but never touched one himself. Each time he was able to resist he felt a feeling of accomplishment and superiority (since he was able to resist while the person smoking was dependent on the tobacco) which allowed him to give up the addiction for good.