Common wisdom says that the time to leave a job is when it's become unbearable. But there are more things to consider than that according to Dory Hollander - a career coach and author of the book The Doom-Loop System.

She says being truly happy with your job means that you can see yourself in 3 or 4 years still liking your work, the company culture and your coworkers. But if that's not the case, it's probably time to move on, even if you're not miserable just yet.

So here are some tell-tale signs that you should think about making an exit:
First: You have a lot on your mind - and none of it is work. When the work doesn't challenge you and you're bored, that's not good.

Next: Your boss takes you for granted. For example, you do something well and you get pigeonholed as the expert in that area. Or you're not considered for new projects. Or even worse, you're known as the good employee who'll do whatever you're asked.

Another clue that it's probably time to find a new job: You've pigeonholed yourself. Some people stay at a job too long because they don't think they could succeed elsewhere. But the longer you stay at one job, the more you feel like your success depends on your environment. And you might lose confidence that you can do anything else. So get out while you can.

Also: Your mood ranges from angry to angrier. No matter how well-respected your work is, when you get a reputation as a grouch, it's not good.

And one more sign you should ditch your job: You feel rotten. Being chronically unhappy can hurt your health. Early signs of too much stress include stomachaches, headaches, and insomnia.

If you think you don't have the luxury of changing jobs because you need the money, then do more than just put in your time. Network with others and develop new skills that'll help you in your next job. And check out the book "The Doom-Loop System" by Dory Hollander.