Ideas and philosophies have a shelf-life. They must be kept fresh and renewed or they will spoil. If left unattended, the same ideas and philosophies that once nourished you and helped you grow can poison you and make you sick. Become aware of new ideas that can refresh your way of life and be open to the fact that your old ideas and philosophies can work for you for some time, but when the shelf-life has passed, those ideas and philosophies could also harm you.