Does divorce occur by saying, "By my divorce, and by my divorce, and by my divorce, I will not smoke until next month," and then smoking before that month arrives?

If you intended for the divorce to be contingent on smoking before the month (ends), and then you smoked, one divorce has occurred, and you may take her back before the 'iddah (waiting period) ends, provided this is not the third divorce. However, if you merely intended to swear by divorce to emphasize something, then no divorce occurs and no expiation is required, because it is a void oath. It is advisable to quit smoking and to avoid swearing by divorce.