Cheers led to Frasier . Sometimes the spin-offs work. Sometimes they don't. As a general rule, the cost of commercial time on television is based on how many people will see the advertising. But who is in the audience also has a powerful influence on price.
Advertisers use ratings to target a specific audience.
Gillette, advertising a new razor, wants to know how many men of shaving age are watching. Revlon wants a show with a lot of women. Lexus and Lincoln will place their commercials in shows that appeal to a mature, affluent, status-conscious audience. There are no hard and fast rules. The price is based on what the market will bear.