Home › Google Adwords Question How long must people watch TrueView in-stream ads on YouTube? By · Sunday, November 23, 2014 How long must people watch TrueView in-stream ads on YouTube? Answer - They play for at least 5 seconds, then users can keep watching or skip the ad. Google Adwords Question GA Gaurav Arora, Digital Media Lead. 10+ years running paid media and tracking for brands in the USA, UK and Canada.