Sometimes making a little money online can be dangerous -- it goes to your head and you think you've got it all figured out...

Throw up some websites, add some sales copy and an order link, repeat often.  Easy money, right?  WRONG.  It could all come crashing down at any time -- the search engines delist your sites, a competitor moves into your niche, your refund rate starts to soar, or your product simply becomes irrelevent.  Your nice monthly income dries up and you're right back where you started. 

The danger of relying entirely on income from your websites makes it very difficult to walk away from a day job and concentrate 100% of your effort online.  Some good advice I've seen is that you should have at least one entire year's worth of your gross salary in reserve before you make the decision to walk away from your job.  This gives you a nice cushion to ride out the variances in your income that will occur sooner or later, and lets you move forward in an aggressive way with your marketing and advertising.

If you work diligently on your online business and manage to save one year or more of salary, you will eventually come to the point where going to work every day is costing you money.  Your time would be better spent on developing a new product or service that you can earn recurring income from -- not trading hours for dollars while working for someone else.  Only you can judge when this point is reached, and only you can decide when the time is right to walk away from employment and go it alone.