Really, term limits is a distraction.

The problem is not in that somebody hold some electoral position for a long time. The problem is that he could not be revoked, bear no responsibility for fulfilling his promises and incompetence.

You could not resolve that problems with term limits. It could even make thing worse.

There is no any point to replace working part with new one. Moreover, new one could be of lower quality and have internal defects.

To resolve the problem with corrupted representatives other means necessary:

1. Responsibility. At the end of term any unfulfilled promise for voters should be accounted like pure fraud with criminal charge, jail time and private assets seizure.
2. Recall. Voters should be able to recall their representative at any time without any exceptions or obstacles. Nobody except voters could fire of impeach representative.
3. Competence. All that mandatory IQ tests and mental health checks. May be some exams to enshure at least minimum competence of candidate.

And sane and good working representative could have his job as long as he able to fulfill the will of voters.

Term limits, especially without aforementioned conditions will attract only candidates with the goal of self-enrichment. They will know that it is a temporary job without any consequences and with nearly unlimited access to power. Guess what kind of people such job will attract.

Moreover, the problem with all that elections stuff is much deeper, really. Freedom of choice is not a freedom at all when it is not you who select availabe options to choose. In ideal world, voters should form their list of candidates, not candidates wannabes themselves or some political parties or whatever. May be even without consent of potential candidates themselves. Say, people of some county know a highly competent man who will be perfect representative for them in power. But he is lazy or just don't want participate in elections or not interested in being representative. There should be some way to convince or even force him to represent his people at least for one term. Something like calling a juror or like. This could be kind of not very fair toward this man, but the benefits for all people of county including himself could hugely overweight any doubts. Politics should be duty for competent and best people, not some stairs for slimy bastards greedy for power and money.