Overall I believe humans should constantly be filling their mind with new ideas and learning more about everything around them, it keeps your mind fresh and alert and allows you to make wise decisions, I think it would be a shame to cut off yourself from learning after you reach a certain age.
I can't understand why anyone would want to stop learning. I graduated from college 1985, and I've been taking classes -- just auditing them, not getting any credit, since 1988. I've also taken many classes through Coursera, an organization that offers free online courses. I love learning for it's own sake. How could anyone take the opposite side and say there's a time to stop learning? That's like dying.
People should continue learning throughout their entire lives. Education is not limited to high school or college. Education and learning should be continued throughout a person's entire life. People are able to learn at all ages, and continuing you education throughout your life will give you a higher level of wisdom. Wisdom is gained through time and learning.
Once a person has given up on learning, that is when life loses its luster. Life gets boring once you no longer have things to pursue. If a person becomes stagnant in their pursuit of knowledge, then their day becomes the same day every day for years. Man was given a mind and rarely uses a fraction of it. Using the maximum expectations aren't much. Might as well read a book.