London businessman Thomas Smith wrote a guide called "Successful Advertising" in 1885. His writings established the Theory of Frequency that is still applicable today.
The first time a man looks at an advertisement, he does not see it.
The second time, he does not notice it.
The third time, he is conscious of its existence.
The fourth time, he faintly remembers having seen it before.
The fifth time, he reads it.
The sixth time, he turns up his nose at it.
The seventh time, he reads it through and says, 'Oh brother!'
The eighth time, he says, 'Here’s that confounded thing again!'
The ninth time, he wonders if it amounts to anything.
The tenth time, he asks his neighbor if he has tried it.
The eleventh time, he wonders how the advertiser makes it pay.
The twelfth time, he thinks it must be a good thing.
The thirteenth time, he thinks perhaps it might be worth something.
The fourteenth time, he remembers wanting such a thing a long time.
The fifteenth time, he is tantalized because he cannot afford to buy it.
The sixteenth time, he thinks he will buy it some day.
The seventeenth time, he makes a memorandum to buy it.
The eighteenth time, he swears at his poverty.
The nineteenth time, he counts his money carefully.
The twentieth time he sees the ad, he buys what it is offering.
One of the reasons why radio advertising and cable TV ads are so effective is the ability to reach a niche audience with a high frequency for a reasonable budget. Of course, playing the same ad over and over again won't be effective -- it will be annoying. They key is to be sure you are building your brand. For this to be effective, you have to focus on your consumers and make an emotional connection with them. The message and positioning is key to ensuring that the ad resonates and connects.