[marcosdumay]

If we are still using the same calendar in 60000 years, and if the Earth's Sun is still so important that we have to adjust our watches, we can start to talk about a leap day.

Granted, this is some 100 times longer than our calendar has lived. And some 10 times longer than any human calendar. So, I suggest we postpone the issue a bit.

[zarzavat]

Indeed, leap day, leap hour, leap minute, etc is a distinction without a difference because either way the solution is the same: do absolutely nothing and let future humanity decide how much drift it can tolerate.