[leijggigf]

Term limits are a good idea in that they cut into the 'monopoly' of career politicians whose primary legislative goal is their own incumbancy.
Term limits are a bad idea and can be considered anti-democratic because they could theoretically prevent the people from electing their true candidate of first choice.

While I think the former concern outweighs the latter, they can Both be addressed in a properly worded resolution:
No candidate for any office shall appear on three consecutive ballots for that office. Any primary or other preliminary ballots are not addressed by or included in this proscription, nor is a campaign for or victory by write-in votes.

Thus if a candidate truly Is the choice of the people rather than just the lesser of two evils and/or the default selection of a bunch of sheeple, they can retain their seat in perpetuity if they can mount a sufficient write-in campaign every third election.