Time Warner’s Turner Broadcasting did its first deal with Netflix that year. Another transaction the following year brought in more than $250,000 per episode for reruns of shows like Robot Chicken and Aqua Teen Hunger Force, according to the former executive. Time Warner figured Netflix’s money would make up for any lost advertising revenue from viewers who watched on Netflix instead of a cable box.
The question of "when does it make sense?" can easily be rephrased as "how much money can I save?" and one of the biggest factors will be the price difference between combined internet and TV service or just internet. These are also the options that vary the most widely based on where you live, and the availability of promotions or contracts that can keep prices down for a short time.