Read some good books on career management which can be found at any local bookstore or library. Since I do a lot of work with technical professionals, I hear about the astounding offers they get on a regular basis. Because they have earned the reputation of being fickle. They are seen as someone who will come in, take advantage of the training the company offers, and then scram for greener pastures. The job hopper is unemployable.
Employees are an investment to a company.
They are the single most expensive overhead item for most companies thus layoffs occur when budgets get pinched. The employee who sticks with the company is a valuable commodity and loyalty is a trait that is desirable to hiring managers. When faced with a new opportunity, turn to your career plan that you have mapped out. Consider your goals in relation to the offer. Career management is important in growing your career.