In this BlackBerry and Bluetooth age of go-go business, more and more of us are working those hours, but not feeling so lucky. And I think that has to do with staying at one company too long.

How long is too long? There is no magic formula, but it's often beneficial to move after being at the same place five to 10 years.

The concept of company loyalty is important, but it is different from the days when our parents tended to work at one place their entire careers. Today, a loyal employee and a long-term employee are not necessarily the same.

Loyalty should be measured by a combination of engagement and length of service, but never by tenure alone. A loyal employee is engaged, and acts as a corporate ambassador by recommending the company to prospective employees and going the extra mile for clients. A long-term one may fit this mould, but could also be stale, frustrated and unsuccessfully looking for a way out.

More than 70% of employees are disengaged from their work and 19% are "actively" disengaged and sabotaging the business, Jeffrey Pfeffer, an acclaimed author and management professor at Stanford University, told a recent Toronto business seminar.

The reasons are varied; but staleness and feeling under-appreciated are high on my list.

There are examples of executives who have risen from "the mail room to corner office" but they are rare in today's world.

Employers know this, especially when filling top jobs. Everyone with career aspirations should know this, too. That is why you should keep your eye on the ball at all times, but begin swinging for the fences after being in the same place for five years or more.

The reason is simple: A 20-year career person who has moved four times is typically more attractive to employers than the person who stayed in the same place for 20 years because he or she has experienced different environments and worked with a larger network of people, shown stability by not jumping too often, demonstrated the ability to adapt, and established a track record of diverse accomplishments.

Again, there are exceptions to this: For example, Matthew Barrett, a former chief executive of Bank of Montreal, began at the bank as a teller, eventually rose to chairman and then caught the eye of a larger British bank. But that is not the norm.

Although I never advocate changing jobs purely for money, the person who has moved every five to seven years is likely making more money than the people who stay put.

Admittedly, all professions are different. In some cases, such as in a law firm setting, high performers can often get equally or further ahead by staying put.

They say a change is as good as a rest. In terms of career, it is often better long term. But you need to be careful about the moves. Here are some pointers when considering a new job:

- Never quit a job or take a new position in haste when emotions can cloud judgment;

- Develop (and write down) a career plan in five-year increments. Where do I need to improve on an annual basis to reach these goals? Where do I want to be in 2010? In 2015? And don't be afraid to alter the plan as situations change; - Don't burn bridges. Being successful over the long haul means having a good name and an impeccable reputation. Besides, it is becoming common to return -- with far greater status -- to an employer several years after leaving;

- Don't move too often. Someone whose resume is checkered with a number of quick moves is seriously jeopardizing long-term prospects for success;

- Make moves that are clearly steps up (or will broaden skill sets that will lead to a move up) and get in writing your responsibilities and opportunities to grow in the new organization;

- Don't let the sparkle blind you. Research the new company, its management style and its culture. If a recruiter is involved in the process, ask him or her the tough questions.

Now, more than ever, your career is up to you. The days of corporate paternalism have gone the way of the electric typewriter and the martini lunch.

To make the most of your career move smartly and with a plan in mind.

- Jay Rosenzweig is managing partner of Rosenzweig & Co., a leading senior executive search firm.