"Term limits" on political careers is an interesting idea. So many people rightly talk about how bad Citizens United and the end to campaign-contribution limits have been for U.S. politics, but career term limits is an idea you seldom hear.
I'll think about that one: Some pols seem to have been able to accomplish great things precisely because of their long careers: e.g., LBJ and the Civil Rights Act. But, now that you mention it, I admit I'm not sure how long LBJ been in Congress when he did all the deal-making with needed to get that one through.
In any case I'd absolutely favor term limits for the Supreme Court, given that the U.S. is the only democracy of its size that doesn't have them.