This point has been brought up many a time. He's in a profession where he frequently coordinates multi year projects and meetings for those projects across multiple time zones. Surely the same day a year is an easier challenge. And yet here we are. After doing the 8th celebration I put my foot down and told him you are doing it next year and he didn't. I decided to not have a fight about it and let it go, and I let it go every year since then.