When Should You Quit Your Job to Work On Your Startup?

So you've got this great startup idea, and you've been kicking it around for a while. 

How do you know when it's time to quit your job, and start working on it full time? 

Allow me to suggest that the following three conditions all be TRUE before you pull that trigger:

1. You are absolutely convinced that you have to build this product, no matter the obstacles. You know there will be obstacles, but you don't care, because you're just that excited about seeing the product come into existence. The whole enterprise feels like a moral imperative -- in other words, not optional. 
2. You're itching to get your hands on the finished product so you can start using it. Not for vanity's sake, but because you legitimately want to use the product yourself. In other words, you're building the product at least in part -- and probably in large part -- because you need it, want to use it, and can't wait for its features and benefits to enrich your life. 
3. You think about your product 24/7. It's taken over your brain, and you are sort of getting to the point that it would give you a rest once in a while. But of course it won't, because it's awesome, and nothing is more exciting to you in life right now than going all-in on bringing it to life. I mean nothing -- not gourmet food, not risky sex, not high-diving, not stock options at your current company, nothing.

If #1 isn't true, then it's questionable whether you have the ambition and drive to power through when the going gets tough: if #2 isn't true, then it's questionable whether you have a product-market fit; and if #3 isn't true, it's questionable whether you're obsessive enough to be a successful entrepreneur. 

If all three are true, best quit your job and get on the grind. You'll never know what happens otherwise.