James W. answered 2d
Middle School Social Studies Teacher w/ 8+ years experience
Yes, other countries have implemented maximum age policies. These are, to the best of my knowledge, only targeting candidates. I cannot think of any modern country that has implemented an upper limit on its voters age.
Here are some examples of countries that have age restrictions:
Iran: the president must be under 75.
Singapore: the president must be under 70.
Germany: Federal judges must retire between 65-68.
Japan: Supreme court judges must retire at 70.
India: Supreme court judges must retire at 65.
Most of these countries cite that these restrictions ensure turnover in positions of power, and maintain their capacity to serve effectively.
The topic comes up in the United States from time to time, but it has never been implemented in law.
Hope this helps!