How do you get around this?

Tasha48 wonders: “What is the average amount of time you should allow your teenager (13 yrs old) on the computer per day (including weekends?) I notice they try to get around this by saying they need the internet to do their homework. I agree in some case they might, but not in all. Another excuse is my friend needs help or I need to ask my friend something online about homework. How do you get around this when you want to monitor computer usage?” Read what others have said and add your opinion here.