I've met Charles Martinet several times at conventions. The dude is an absolute delight. He is deeply connected with Mario as a character, far beyond what is normal for a voice actor. He knows everything about Mario. Mario has been his life for nearly 30 years. He has absolutely earned the right to retire from Mario if he so chooses.
One thing that I thought was interesting, apparently he doesn't have a home. He travels so much for conventions that he just lives out of a suitcase. Everything he owns is in that suitcase. He just goes from hotel to hotel.