On weekday afternoons you won't find Fayetteville teenagers Dane and Savannah Shields checking their Facebook online or watching television. That's because parents Todd and Karen shields have set some boundaries. No T.V. or computers are allowed in the bedrooms.

"Where we do have screen time is places that are pretty public. So, we know if they are on, and they know that we know. so we're keeping a tab," says Todd.

However, ask any parent and the real challenge comes at bedtime. For Todd and Karen that sometimes means taking away the cell phone. "We have found that's a temptation that they really aren't mature enough to handle," he says.

In fact a new study shows todays teens spend an average of 7.5 hours a day on digital media devices. University of Arkansas Psychologist Dr. John Marr says it's a problem parents of teens need to be aware of.

"Parents tell me, their kids will take their phones to bed with them. And when parents think they are asleep, they are talking on the phone underneath the covers, they are playing games."

According to Dr. Marr, too much time spent on any media can cause teens sleep and grades to suffer. "We tend to talk about the consequences of what will happen if they spend too much time on a Facebook or T.V. The fact that they don't do their homework, they don't practice the sports they are in," says Karen.

These parents did point out not all time is wasted, when it comes to technology.

"They may not necessarily want to talk to their dad, but they'll text their dad all day. So, that's one way that I've really found out where they are, what they are doing, who they're with, what's going on," says Todd.