Examinations are a key factor in school education, yet with regard to its function there have been many arguments. Read the news

Professor
    There are three reasons for repeating the same TV commercials so often.
    The first reason is simply a matter of economics. The production of even a 30-second commercial may cost as much as $50000. Obviously it would be far too expensive for a company to produce a new ad every day, or even every week.
    The second reason is to make sure that as many people as possible will see it. This is what advertising researchers call "market saturation". The more often a commercial is shown, the more people will have a chance to see it at least once. People who watch a lot of television will see the commercial many times—and will probably become bored by it—but people who watch television less often or confine their viewing to a few favorite programs, may see the ad only once or twice.
    The third reason is the belief that repetition helps to imprint the message on the mind. Some advertisers differ in their opinion about this. Some feel that repetition—even to the point of irritation—is good; the irritation itself is supposed to make people remember the product. Others argue that repetition to the point of irritation can annoy television viewers so that they will purposely avoid the product. While this point may be debated, there seems to be no question that a moderate amount of repetition makes the ad memorable, and certainly more persuasive than a single presentation.