Your habit is the behavior that goes with your tobacco use, such as lighting a cigarette when you get out of school.Reasons not to smoke. * Expensive (over $1000 a year for a pack a day) * Bad breath * Stained teeth and hands * Cough/sore throat * Problems breathing * Feeling tired and out of breath * Wrinkles (more, sooner) * Arguments with parents, friends * Cancer risk * Heart disease risk * Gu