How Much Time Should You Invest in your Part-time Work?

How much time is a part time job worth?
Do you freelance after you get off work?  I know a lot of people who do.  Most of them write blog articles and they get a few cents per word.  That's hard work and it takes a lot of time.  Unless you need the money to pay the bills you should save it up and wait until you need to take time off from your main job before you dip into that money.  I will explain why.