Most of us probably had mentors in graduate school and may still maintain contact with them. But they may not be available every time we need their advice or guidance. I suggest that we all have a mentor that is always available, night and day, every season and semester, for every situation and circumstance.
This is your Inner Mentor (IM), also called your inner guide, self, voice, spirit, higher power, soul, subconscious, guidance system, intuition, even your heart or gut. It has more power than your department or committee chair, the dean of your school, and even the guy who issues your annual parking sticker.