1. Your job has been misrepresented. Often, new assignments or rotations are not quite as described. It happens at every level. A CEO told me he was hired and given the task to build up his agency's revenues; he was not told that the agency was up for sale. A recent college graduate was hired by a small agency as an assistant account executive. She found herself sitting at the reception desk. If a job has been misrepresented, the issue should be addressed with your supervisor or management, the sooner the better. If the answer is unsatisfactory, start your search.

2. You have been passed over. As you become more senior, the executive pyramid becomes narrower. If you are passed over, it is important to determine the reason you were not promoted and what it means to your future. There are people who have been passed over only to find that their company had a better job waiting for them. Be sure to get the whole story so you can determine if it's time to look.

3. You lose your mentor. Most successful people have a mentor, either formally or informally. A true mentor is a career advocate who knows your strengths and can influence your career advancement, often a current or former supervisor. If a mentor leaves or is promoted away, it is important to talk with him or her to determine an appropriate course of action.

4. There is a restructuring of your company or client or a change in mission. Companies and people change. Clients change strategy necessitating a change in direction. Over the years small ad agencies have morphed into consultancies and given up their advertising clients. New management may alter corporate priorities. You need to evaluate these shifts to determine an appropriate course of action for yourself.

5. You become lost in corporate bureaucracy. The following scenario happens all the time: You have not had a raise in several years. You suddenly have a new manager who won't or can't promote you until they get to know you better -- perhaps in another six months. Your human-resources manager is either unwilling or unable to become an advocate. So you are caught in the middle. It may mean that it is time to look for a new job.

6. Business is lost. Because clients control fees and staffing, when an account is lost or the budget is reduced, the best employees may be vulnerable. The loss of an account or a diminished budget may indicate you may lose your job; it is simply easier to eliminate an entire group than to cherry-pick the good people for rotation and reassignment.

7. Your career path is diverted. People get hired for one job and put into another; this often happens between the time a job offer is accepted and the time an employee starts the new job. It leaves them with no opportunity to react or object. But it also happens to current employees. I interviewed an exec VP who was up for rotation. He was asked to move overseas to a secondary foreign market with a better title and an excellent lifestyle. But he knew it was not a mainstream job and understood that the new president was giving him a not-so-subtle message that it was time to move on.

8. It no longer feels right. The signs are subtle. If you are in touch with your feelings and carefully observe your environment you may have noticed subtle changes in the way you are being treated: calls not returned, being excluded from meetings, someone taking over your responsibilities. These are indications that something is wrong and you must determine next steps.

9. You are bored but can't get a new assignment. When you are doing a good job, your competency may be rewarded by leaving you in place. Creative people get rotated to keep them fresh. It's not always so with account people. Because they are the keepers of the relationship, a rotation may upset the apple cart. Doing one thing for too long can produce ennui. Boredom creeps up on you over time. If you're beginning to be bored and can't get your assignment changed, it may be time to begin a job search.

10. You're grossly underpaid. You should always change jobs for opportunity, not money. However, there are times when a move is in order. If, after three years, you get a 5% increase, given the rate of inflation, you're actually losing money. If your company postpones its scheduled employee reviews and raises, it's easy to fall behind the eight ball.

Sometimes staying in place and waiting things out is the best course of action, of course. But if you do decide it is time to look for a new job, prepare yourself. Given the economy, it may take a while.