Generally, the rationale of term limits seems to be to prevent a dictatorial or monarchistic system from emerging.

However, consider the rise of the National Socialists in Germany: In 1930, they first got a result > 3% in a federal election. By the end of 1933 all other political parties were banned. No practical term limit could have prevented this dictatorship, even though they never got more than 44% of the vote in a federal election, i.e. never enough to really change the constitution by democratic means. So we definitely know that term limits are not a completely reliable measure.