Term limits or mandatory retirement age for elected politicians and legislators?

Try term limits first! It probably would solve most negative issues related to lifelong career politicians!

I also think term limits are superior to age limits! E.g. would not prevent an older citizen from becoming an elected representative?

One example: With term limits, most likely the man from Scranton, Pennsylvania (Joseph Biden) would have never become the disaster of the 46th President!

Second example: The term limits imposed on U.S. Presidents since 1951 seemed to have worked quite well so far!

Apparently, in some Western democracies there is too little competition for citizens to become elected representatives and to challenge incumbents. For this and other reasons (political party machines etc.), too many elected politicians manage to hang on as members of parliament for too many years. 

The large caste of lifelong career politicians is a serious issue and a grave defect/flaw of Western democracies. For a citizen to become an elected politician, the office should be a temporary occupation to serve the community before another citizen is elected.