The pros and cons of term limits in Congress have been debated pretty heavily over the years, and there are many opinions among experts on both sides of the issue. Most experts agree that the main advantages of term limits are the potential for a reduction in corruption, an increase in the number of new ideas flowing into the legislative environment, and politicians who might potentially focus more on effective governance instead of constantly worrying about reelection as a top priority. Some of the potential negatives include a constant influx of inexperienced politicians, and the potential consequences of congressional leaders who don't have any concern about voter opinions.
Many experts believe that politicians have a tendency to grow more corrupt as they spend more time in office. Some blame this on the legislative environment, while others simply cite basic human weakness and the tendency of people to succumb to temptation if they are exposed for too long. Term limits are often seen as one potential solution for this problem. By shortening congressional terms, proponents hope to make sure that nobody sees becoming a congressional representative as a viable lifetime career choice, leading to more people who get into politics for noble reasons instead of a simple desire for power.
Another possible advantage of term limits is the potential to change the behavior of people who are elected. It is pretty common for politicians to be accused of constant jockeying for electoral advantage instead of voting based on their real beliefs. For example, a political leader might decide to oppose a plan even though he knows it could help people simply because it was proposed by someone from the other side of the political spectrum, and voting for it might make it seem like he is siding with a political enemy. Some hope that by reducing the constant concerns about being reelected, term limits in Congress could potentially reduce this kind of political gamesmanship. Term limits would also potentially result in a constant influx of new people bringing new concepts and philosophies to the table, which is often seen as an important advantage.
Sometimes people stay in congress for a very long time, and they may become very skilled as legislators. Term limits would mean that nobody spent too much time in Congress, and after every election, there would be a huge class of rookies who wouldn't fully understand the insider tricks needed for effective legislating. Some people believe that this lack of understanding about how legislation works in a practical sense could be so disadvantageous that it might outweigh any potential advantages of term limits in Congress.
Another concern is that term limits would shorten the careers of some of the best congressional legislators. People who have no history of corruption or political gamesmanship would be forced to leave along with the bad apples, regardless of their performance or merit. There is also a lot of worry that it might not always be such a good thing if congressional legislators ignored the politics and the concerns of their constituents while in office. Legislators without any concern about politics might do more good in some cases, but they might also pursue ideologically unpopular ideas without a second thought.