What is it more fruitful for an employee to work in a company?? 1. for long time in same company. 2. regularly change the jobs.

It depend on your ambitions and your goals, which means what would you like to achieve in your carrier. Regularly change jobs doesn't secure development or climbing in the carrier.

My answer may not fit all employees, but a great majority of us.

There are pros and cons for both approaches.

Firstly - one stays in the same company for a very long time - his learning stops after some time, his exposure to the world is limited, most importantly he only knows how to do things the way his organization does it, and after many years, he himself will be unsure of himself when he wants to make a change. He is likely to reach a stage when he will not trust his own capability in the outside world because he's never seen it.  The positives are that he will probably be very comfortable and  know almost everyone in the organization, he will understand how to get things done in the organization, and gives the organization no replacement troubles - because he is stable.

Such people are not too networked, as they remain happy where they are.

Now the type who shifts often - I've hired over7000 people in my career, and most HR people consider such people as unstable. But what we must also realize is that a guy who can talk his way into several top organizations needs to have something special in him simply because each organization puts him through their own filtering process. So such people are likely to be sharper, faster, more impatient (if they become unsatisfied they quickly look out), and more knowledgeable because they've seen how other organizations work. They will be able to come up with quicker and faster solutions to problems because they can visualize how it worked in one of their previous organizations. Such people are also very well networked, and they can leverage on their networks to help organizations.

dependent about work nature and the staff