Term limits are a silly idea.

Independents are only powerful if they get to put in considerable time into the position - like Bernie.

However, if you're in a party, a term limit is no issue. The party just finds someone else for this role, and shuffles you into another one.

What term limits say is this: "People are too stupid to vote correctly [which is probably true] so we'll prevent them from voting for the same person too often." This doesn't fix the problem of incompetent voters at all.