To extend to this, when I was in college, my grades suffered because of my unnecessary internet usage (reddit, hn, facebook, all that stuff). So after failing to keep up my promise, I decided to actually leave my laptop at home which is 4+ hours away. I didn't have a computer nor smartphone at the time, so all I had left in the house was material necessary for studying. Needless to say, I jumped from being about 80th percentile to 2nd percentile in the class and this allowed me to gain more theoretical knowledge than my I did in my 19 previous years.

Sad thing is, now that I'm working, I have internet and computer back at home, and I waste a lot of time on it...