If people want fresh ideas, then they will elect someone new, but it is undemocratic to deny them the option of voting for a candidate simply because he or she has already served for a few terms. While this is a good point in theory, in practice the advantages of being an incumbent prevent elections between longtime office holders and new challengers from giving voters meaningful choices. It is often nearly impossible to raise money for a campaign that challenges someone who has held an office for a long time, so the voters never hear the message of the challenger. Voters usually choose incumbents over their rivals, about whom they usually know next to nothing, but that does not seem like much of a choice. The wishes of the voters would be better served by a totally even election, which would require restricting the ability of politicians to hold the same office indefinitely.
Experience is important in any job.
Term limits would require that our leaders be novices. You wouldn't want to be operated on by a doctor who had never performed surgery before or to be represented by a lawyer who had never been to trial before. The same rule holds for politicians. Term limits would remove all senior members from these committees and destroy the continuity of committee membership from term to term. People who are elected to important positions will likely have experience in similar areas.