Jason Morrow, Utah, USA Your question reminds us of a friend of ours, an investment manager at a highly regarded company in the midwest, who drove to work one morning, parked his car in the usual spot and then found he simply could not bring himself to get out.

"I guess I stayed on the farm one day too long, " he joked later. When we asked him what went wrong, he answered, "It wasn't one thing. It was everything". No wonder he drove home and called in his resignation.

Obviously, most people don't decide they've overstayed at their companies in such a dramatic fashion.

Usually, angst about work creeps in, and then builds until it consumes you. And that can happen early or late in a career.

Gone are the days when, after graduation, you took the best available job and stayed for as many years as you possibly could stand, frustration be damned.

These days, it is not unusual to hear of perfectly legitimate careers built on multiple job stints. So how can you tell when it's time to move on? We wouldn't set out specific criteria as much as offer four questions to help sort out an answer.

The first is so simple it almost goes without saying.

Do you want to go to work every morning? Does the prospect of going in each day excite you or fill you with dread? Is the work interesting and meaningful or are you just going through motions for a pay cheque?

Are you still learning and growing?

We know of a woman who worked in consulting for seven years. She loved her firm and had planned a career with it, but suddenly started wishing every weekend was five days long.

"Basically, I felt like we were putting together massive books in order to Q A make recommendations to people who knew more than we did, " she said. "Every day at the office, I felt a little bit more of a hypocrite." She now works on the "front lines", to use her phrase, in the marketing department of a retail company.

Second, do you enjoy spending time with your coworkers or do they generally bug the living daylights out of you? We're not saying you should only stay at your company if you want to barbecue with your team every weekend, but if you don't sincerely enjoy and respect the people you spend 10 hours a day with, you will eventually decide to leave your organisation. Why not make the break sooner rather than later and start cultivating relationships at a company where you might actually plant roots?

Third, does your company help you fulfil your personal mission? Does it require you, for instance, to travel more than you'd like, given your chosen work-life balance?

Does it offer enough upward mobility for your ambition?

There is no right or wrong answer to questions such as these, only a sense of whether you are investing your time at the right or wrong company for you.

Finally, can you picture yourself at your company in a year? That's how long it usually takes to find a new, better job once you decide to move on. So peer into the future and predict where you'll be in the organisation, what work you'll be doing, whom you will be managing and who will be managing you. If that scenario strikes you with anything short of excitement, then your runway is too short. Or put another way, you're just about to stay too long.

We're not suggesting people quit at the first inkling of discontent. But it makes little sense to stay and stay at a company because of inertia. Unlock your door and get out.