How much is too much?

I spend any were from 5-60 minutes on the computer each Monday through Friday. Howver, I usually spend 1 hour every day. I not usually about texting on my cell phone. Yes, the parents should limit the amount of time , but only the child isn't getting good grades. It the child is doing good in school them they should be able to spend as much time as they want on the computer.
The possible problems of spending too long the computer is the time, spending too long on a computer cam get the kids to see things shouldnt, but their parents should be keeping an eye on them.