What are the pros and cons of having 1.) an odd number of justices on the supreme court 2.) being appointed for life in it

THIS IS JUST AN EDUCATED GUESS. DO NOT BLAME ME FOR LOSING POINTS. THANK YOU!!

1). An odd number of Justices on the Supreme Court make it where there can't be a tie in a case. A con to having this kind of system, majority will always rule, even if the ruling is unjust.
2). Being appointed for life means the Justice should go unbiased and understand what a good and moral ruling is. A con to that is, unless taken from their position, they have the power to do bad things.