There are people who believe they should keep working at the same organization for life, while others prefer to move their jobs to different organizations. As both ideas have advantages and disadvantages, it is not easy to say which is right. However, as far as I am concerned, we do not have to be loyal to only one organization throughout our professional careers.
The advantage of the former idea is that we can build professional careers in relatively stable and predictable environments. Surrounded by people who know us well, we can gain and foster our skills. Also, it may be easier to imagine our career paths in one organization for long span. However, working for only one organization might not offer us various aspects of view to look at our careers. It may cause us to narrow our thought to structure our careers to maximize our ability and performance.
On the other hand, working at several organizations gives us wide range of view to think about our careers. If we are lucky, the new job gives us useful skills, and better salary and work environments. In my experience, changing my job provided me with opportunities to try new things more stimulating and challenging than before. Also, the new organization offered me more flexible work environment which enabled me to have my children and pursue my professional career at the same time. However, moving our jobs always comes with risks. We do not really know how the new job and its environment are like until we actually start working at the organization. Unfortunately, there are a lot of people who could not get what they wanted for the new job.
In this way, both ways of thinking toward jobs are reasonable as well as risky. However, in my opinion, it is not necessary to stay at only one organization all through our professional careers. As long as we choose organizations carefully, it is possible to make our careers more fruitful by changing our jobs.