Honestly... there's not a set number. For some people even just 1 is 1 too many, but for others they can drink a couple every day, and it's not a real issue. The key is to evaluate whether or not it's interfering with one's ability to function normally, or to maintain normal healthy relationships. Keep in mind too though, that if one is drinking an excessive number, that it can cause liver and kidney damage. So moderation is really the best course.