One of my systems runs 24/7 for monitoring servers and websites. + The system i work with runs 4 - 8 h a day.
I use my computer daily at least 2hours a day. And i spend all 2hours mostly on digital point. Without computer now a days life is impossible and very hard.Because most of work with the help of computers.
but if you are using social networking sites than you are waisting your time you should use computer to gain knowledge