The average American spends 4.5 hours a day in front of the television, according to All Business.com. The highest TV audiences are available during prime time, or the time roughly between 7 and 10 p.m., depending on your time zone. Although advertising on prime time typically costs more than advertising at other times, it offers many advantages.

Large Audiences

Despite all the activity on computers, tablets and smart phones, 97 percent of all video viewing in the U.S. still occurs on TV, according to Advertising Age. A popular prime-time show, which in 2013 would include "NCIS" or "Dancing with the Stars," can draw an audience of 15 million to 19 million. While buying air time during these programs is expensive, the volume of sales generated from reaching out to such a huge group of potential customers will often offset that investment.

Perception

TV allows you to convey your message with sight, sound and emotion, lending instant credibility. In fact, people associate being on TV with prestige or importance. About one-third of prime time viewers believe companies that advertise during prime time are more committed to quality than those that do not, according to MarketingCharts.com.

Engaged Audiences

Audiences are often at their most alert and engaged during prime time, according to AllBusiness.com. While not everyone is pleased that more people vote in "American Idol" contests than in U.S. presidential elections, it still proves just how powerful TV can be as a tool for getting -- and holding -- the attention of millions of viewers.

Life Outside of TV

Millions of people watch the Super Bowl as much for the commercials as for the game, and these commercials are often remembered even decades later. When combined with social media such as YouTube and Twitter, a clever TV ad can take on a life of its own.