Tell a Tale on Radio
If you're running a radio commercial, figure out the amount of time you'll need to make your point.
Sixty-second ad spots cost only 20 percent to 25 percent more than 30-second spots. But, of course, the radio audience attention span is notoriously short. Most advertisers buy 30s. It's the default purchase: Buy 30s unless you feel you'll benefit from 60s. If you're convinced you've got a more complex (and more riveting) tale to tell, go with the 60s.
Excerpted from Knock-Out Marketing: Powerful Strategies to Punch Up Your Sales