I had an idea of a species physically living to about the same age we are, but because everything's so spread out and long to get to places, schedules and conflicts last centuries. Like, you go to school on Jupiter, you have an assignment, and it's due in eight years and two days, and you go back to your house in Mars, it's a four year trip each way, so you go there, four years have passed in suspended animation, you spend two days writing the paper, then fly back and turn it in.
Like Aperture Science running space travel. Literally dragging out people''s existence for millenia in order to make appointments. And it's not like 'buh I'm just gonna go slow and rob everyone in my fast life,' EVERYONE'S hooked up like this.