I really do not know. But I think it has been about every three years. There a minor refurbishments and major refurbishments as well. The Mariner was really overdue as it was delayed for year and it was showing the wear and tear. I hear it looks great now looking forward to seeing the change in November. One of our brilliant posters like Marc and some others who really follow this may know. Something I SHOULD know but have not paid attention to in the past.
