The data showed that smokers took on average nearly three times as much sick leave as did non-smokers, and significantly more time off than ex-smokers as well. The more recently an ex-smoker had quit, the more absenteeism they still showed. So too, it took quitters 12 months to become more productive than current smokers. Past that one-year mark, though, ex-smokers were on average five percent more productive than smokers. Perhaps the greatest incentive to give up smoking, the scientists found that current smokers were the least satisfied with their lives, based on their answers to a standard questionnaire.