How much screen time is too much?

We're surrounded by screens—at work, at home, on the go—and so are our kids. Yes, screens can sometimes be a saviour, but screen time is a difficult thing to manage. How much is too much for your little one? Is your big kid looking at things they shouldn't be? What about quality? Are they learning something or just buzzing out? Mel and Evanka ask Kim Shiffman, Editor at Today's Parent, the tough questions about one of the biggest sources of parental guilt.