How can i keep a balance between life and WoW?

So I just started on World of Warcraft. I have already found the game very addicting. I have seen my friends fall into the abyss of Warcraft. What is a good way to keep my social life and WoW balanced? The many people that tell me they wasted 4 years of their life with the game. I love the game, but understand i need to draw a line. Any suggestions on a sorta schedule of playing WoW would be great.

I have a standard policy where I only play at the end of the day, when I have accomplished all that I need to for the day (wife and kid keeps me running)

This usually only allows me to play maybe 1-3 hours a day (5-6 days a week) but it keeps my priorities on what is important.