"How long does a human live on Mars?", my wife asked.

Me: "The same, about 70 Earth years."
Her: "How long is that on Mars?"
Me: "How long is that on Earth?"
Her: "Huh?"
Me: "How long is it anywhere?"

It's so easy for us to believe that we know exactly how all of this works - probably because we desperately want to believe. It's pretty obvious, though, that we don't - we can't even move around in our own dimension without our systems quickly becoming nonsensical.

Go ahead, set your alarms, synchronize your watches, datestamp your blog entries...
...but don't get too caught-up in it, okay?
...it's just a model.

It's quite possible that everything is actually happening at once, and that time is just a funny idea we came-up with to help hunt for food. :)