Classic career advice says that you should aim to stay at every job for a minimum of one year — but how do you know when it’s time to move on?

There’s been a lot of talk in the past few years about the dramatically changing workplace and how shorter tenures are becoming the norm. Employees just aren’t staying put at their desks for 20 years at a time anymore, especially in the IT and tech arenas. For people navigating the uncertain waters of their careers, this can cause some pretty serious feelings of instability. How short is too short, and how long is too long?

The answer depends on your particular situation.

According to a recent article by Forbes, a good guideline is somewhere between eight months and six years. Here’s how it breaks down:

Eight Months: Only leave if you are truly miserable at the job and think that staying will harm your career.

A Year and a Half: According to the article, this is a good minimum to shoot for because it suggests you passed a review cycle and chose to leave of your own accord.

Four Years: A solid 48-month span of working for the same company looks great on your resume because it’s not too long and it’s not too short. It shows that you’ve had ample time to learn, grow, and get promoted.

Six Years: If you’re staying at a job this long, it should only be because you’ve been promoted to a position of responsibility where you’re working on important projects with senior-level staff.

But, as with every set of guidelines, there are exceptions to the rules. If any of the following apply to you, it could be time to move on — even if you haven’t made it to the 48-month benchmark yet:

You’ve Stopped Learning.

Money is only part of the value our jobs give back to us for our hard work. If you’re learning nothing new, there’s a problem. Your current job is what prepares you for the next one, and if you’re not learning and growing, you won’t be prepared.

You’re Being Underutilized.

Are you sitting on a goldmine of ideas and know-how, but nobody sees it? There’s nothing more frustrating than wasting your potential on jobs that don’t value your skills. Find a job that not only uses your full skill set, but also challenges you to expand it.

Your Career is Stagnating.

If it’s been more than a little while since your last raise or promotion, it might be time to move on. Prepare for your next career move now by either getting that promotion, or moving somewhere else that will raise the bar of your career.

You’re Clinging On.

Sometimes we are the ones who refuse to let go of our jobs. Whatever the reason for clinging, remember that being too comfortable in your current job will most likely make it harder for you to get comfortable in the next one.

Your Ideal Job Is Within Reach

Have you been offered your dream job? Then take it! It’s okay to take a calculated risk with your resume once in a while if the payoff is really worth it. It’s your life, after all, and sometimes the best opportunities don’t come twice — so seize the day, but be smart about it.