There are many deeply personal reasons to change your employment situation. However, from a purely strategic point of view, there are four good reasons to change jobs within the same (or similar) industry three times during your first ten years of employment:
Reason #1: Changing jobs gives you a broader base of experience: After about three years, you´ve learned most of what you´re going to know about how to do your job. Therefore, over a ten year period, you gain more experience from "three times 90 percent" than "one times 100 percent."
Reason #2: A more varied background creates a greater demand for your skills: Depth of experience means you´re more valuable to a larger number of employers. You´re not only familiar with your current company´s product, service, procedures, quality programs, inventory system, and so forth; you bring with you the expertise you´ve gained from your prior employment with other companies.
Reason #3: A job change results in an accelerated promotion cycle: Each time you make a change, you bump up a notch on the promotion ladder. You jump, for example, from project engineer to senior project engineer; or national sales manager to vice president of sales and marketing.
Reason #4: More responsibility leads to greater earning power: A promotion is usually accompanied by a salary increase. And since you´re being promoted faster, your salary grows at a quicker pace, sort of like compounding the interest you´d earn on a certificate of deposit.
Many people view a job change as a way of promoting themselves to a better position. And in most cases, I would agree. However, you should always be sure your new job offers you the means to satisfy your values. While there´s no denying the strategic virtues of selective job changing for the purpose of career leverage, you want to make sure the path you take will lead you where you really want to go.
For instance, there´s no reason to change jobs for more money if it´ll make you unhappy to the point of distraction. In fact, I´ve found that money usually has no influence on a career decision unless it materially affects your lifestyle or self−identity.
To me, the "best" job is one in which your values are being satisfied most effectively. If career growth and advancement are your primary goals, and they´re represented by how much you earn, then the job that pays the most money is the "better" job.