I used to, but I don't anymore as I have gotten busier with other things. My usual playtime for a single round played from start to finish is around 5-8 hours, give or take. I usually play it in sessions of about two or so hours and then come back to it later or another day. I think if I had to estimate, I finish a civ5 game every 3-4 days or so on average. I think taking breaks is also good as you can think about what your strategy is like and what you can do next when you come back to it. You just don't get that when you play it all in one big session.
I play standard speed, always. The other speeds don't really convenience me.
I play standard speed, always. The other speeds don't really convenience me.