The idea of voluntarily leaving your job for any reason can be a gut-wrenching prospect. Perhaps you know folks who lost their jobs during the Great Recession, or perhaps you simply dont want to deal with the fear of the unknown. Indeed, making the decision to quit your job the place where you spend most of your waking day is not a decision anyone should make lightly.

But the reality is that most people will not spend their entire careers with a single employer, and at some point in your career trajectory, you must consider moving on if you expect to get ahead. Here are four key signs that you should look for to help you decide whether you need to quit your job to advance your career:

1. You sense you have become stagnant: You are only as good as the tools on your belt, and when those tools are starting to look dull and worn out, its a sign you need to do something to sharpen those tools or look for a whole new tool belt. If youve lost passion for your job, if you sometimes dread going to work, if you struggle to stay motivated, then you may have hit a wall and become stagnant, according to Inc.com. In every job, you should always seek to be learning and growing. When those days of personal growth become fewer and further between, we either must find a way to reinvigorate that passion and growth or move on.

• Youre too comfortable: A wise mentor once told me, Get out of your comfort zone. The longer Ive been working, the more I realize that there is no growth without discomfort. While it may feel good to be the only one who knows how to do a task well, or to be more skilled and knowledgeable than your boss, this level of mastery comes with a downside: It makes us feel complacent. And the more complacent we feel, the more likely we are to want to stay in this secure, familiar place. But feeling dormant because were on top is also a sign that were optimally positioned to jump ship for a more enriching professional opportunity.

• Youre capped out: One of the most frustrating workplace experiences we can encounter is seeing other people get promoted whom we believe are less skilled and less experienced than we are. Although we grumble quietly with co-workers and perhaps even bring up this issue with our superiors, sometimes nothing changes and our career growth essentially gets capped out. When it becomes clear we simply arent going to grow into management and leadership roles, we absolutely should not retreat and allow ourselves to feel undervalued we should use this unfortunate situation to motivate ourselves to look for job opportunities elsewhere. If you still arent convinced this is the strategy you need to take, consider this: If youre being treated unfairly and you stay anyway, then youll start to distrust and resent your companys leadership, according to Forbes. Why would you want to stay in a job that makes you despise your employer?

• Youre getting paid too much: You may be thinking, Why in the world would I want to leave my job if Im getting paid too much? But the reality is that this happens often and its not necessarily a good thing. Essentially, what happens is companies know they are limited in the opportunities and growth they can offer top-notch employees, so they overcompensate these employees as an incentive to convince them to stay. On the surface, this sounds like a great deal, and indeed, many employees accept the extra money and stay. But employees who are being overpaid are actually likely to get in a rut career-wise. Thats because they arent learning anything new. If you feel like youre being paid too much for a job you could practically do in your sleep, you should start exploring other options. The good news is when you finally make the leap, youre likely to land a more challenging job AND stay at the same pay level. Another thing to consider is that employers will often cut their highest-paid employees first when tough times come, especially if those employees are being paid more than they are actually worth. Sticking around for an under-utilizing job that overpays could be the reason you are out of a job when the next recession hits.

No one will tell you its easy to walk away from a job that seems to have good things going for it. But when you start to see the telltale signs that its time to move on feeling stagnant, feeling too comfortable, being capped out, and being overcompensated perhaps it will become a little easier for you to come to the realization that sometimes you need to quit your job to advance your career.