I oil my board every month with mineral oil, which is cheap and recommended by the maufacturer. I also heat it up in the microwave before applying it to the board. I read this somewhere. My board is 3 inches thick and after 4 years, I've never gotten a single crack.
The thought of putting a cutting board oil in the microwave is such a lo-tech/high-tech brainstorm. (Thanks, Lori!) MGR