About 9 years ago I attended a funeral of someone whose daughter then worked at Fox News (doesn't any longer). Before the Mass started I overheard two men discussing why they didn't watch Fox: (1) too many commercials and (2) too much of people yelling at each other.
TV and radio both use what is called a "Flex Clock," with approx. (flexible)times slotted for commercial breaks in each hour. Usually, the first break is at :10 or :18 minutes past the hour, then again at the bottom of the hour, at :40 mins, then finally a break at :50. In TV they often have a final break just before the top of the hour at the end of the show.