In this regard, radio is an unusual medium. While most TV viewers would be outraged by a grating, low-budget commercial that aired 10 times an hour, this is less of an issue when it comes to radio, because it's easier to “tune out” a repetitive ad when you're listening to it rather than watching it.
In fact, some of the most successful radio ads of all time have been grating and repetitive, incorporating screeching voices, silly sound effects, and intrusive music.
Granted, you want your own radio spot to be more tasteful (though not so tasteful that listeners don't pay attention to it!), since you don't want people to develop negative associations when they hear the name of your law firm.
Only a consultant can tell you for sure, but repeating your ad five times an hour may not be a bad idea, and even greater frequency may be indicated if you're willing to pay the price and you know that you have an interested audience on the other end.
If you're an attorney who specializes in car accidents, for example, it might be a good idea to repeat your ad multiple times during the morning and evening rush hours.
In the end, you have no choice but to do some intensive research and figure out;
- Your target audience
- What stations your target audience listens to
- What time of day they tend to tune in.
Once you've gathered the data, repeating your ad multiple times in the course of an hour will often turn out to be a good thing, rather than a bad thing.