There are lots of professions which presuppose dealing with people, but just a few of them may require such a unique skills as guessing a person's age without any specifi documents. Guess who we are talking about? Barmen, of course! Every day, or we'd rather say every night these people risk their job trying to decide whether the people in front of them are over or under the drinking age. However, you may say that it's not that difficult to guess if you are an experienced person. Okay, let's test and prove!