The older, the wiser.
越老越聪明。/姜是老的辣。
Life makes a wise man smile and a foolish man cry.
生活让智者微笑,让愚者哭泣。
a wise move / choice / decision
明智之举/明智的选择/明智的决定
It is wise to have some money put away for old age.
存钱养老是明智之举。