It's very difficult to tell the difference from the inside. Am I just bein stubborn, or do I just need to hang on? It's essentially a matter of predicting the future, and you don't have enough information.
Having gone through this in the last six months, I found I had more than enough information, and what was standing in my way of leaving was a somewhat complicated mixture of emotions surrounding the act of leaving. Of course, a clear headed look at the circumstances let me wipe all those emotions away, and I left at the right time, and without regrets.
For devs, a great rule of thumb to keep in mind is simply this: When the paychecks stop, so do you. The odds of any startup getting anywhere drop off a cliff once the money runs out, and the founders are running around desperately, talking about commitment and challenge and reward.
One way to think about it is by asking yourself, "If I were just entering this situation today, would I take the job/join the project? Or would I see it as a fruitless endeavor?" That can help get your mind out of thinking about what you've already sunk into the job.
