New blood is necessary for a vampire to survive, so does the enterprise.  Revitalization and energy are essential for any enterprise because fatigue and depressing atmosphere will never bring good luck instead it will lead to failures. Sometimes, indeed, those power should step back after five years to offer the chance to anyone who are capable of the position.      Though the claim restricts the time during to five years,it does not actually matters whether it's five years or not. In term,it means after several years when the leader starts to familiar with the enterprise is the turn for a big move on the Personnel readjust.There is no such thing as perfect. There exists only behaving better and better. When the old leader accomplished a big success during his ruling period, the company is likely to stay in the stasis situation, the best is keeping the old look, but even that is difficult considering the satiated emotion with the current accomplishments. Thus the firm will not go further with the current leader still clinging on to his power. The fitness club in my society's story is one of those "one-night-changing" lucky ones. People in my suburbs seldom goes to the local fitness club due to the large percentage of seniors people. And the club's young and energetic styles surely are not in line with the local lifestyle. Under this situation the company change a new manager and he thus makes a big plan for the club-- especially alters the intended customers to youngsters. The big change is successful, new methods, new team, new equipment, new profits.        Considering the case to a large scale, a country's leader should varies from times to times. In american, the term limits for the presidents play a big role in consolidating a democratic culture. The election is hold every 4 years, whether to stay or not, speaks for the residents. Mr.Bush's eight year leadership is due to 911, which has bring americans anxieties and fearfulness of unsteady governments. Even though people are unsatisfied with the Bush industry, people also seek of tranquility and stable so that the term lasts for 8 years. The Roosevelt's leadership is also the same, during war when people are in search of stable do they permitts the continuety of holding the power.  The term limits are likely to encourage accountability and reduce excesses of power.         Energy and new blood on the other hand, can erose unstable and adventurous issues. Especially during wars and those periods which needs constant environment(让步）            In sum ,.......