Topping off coffee

My dad seems to have a cup of coffee that lasts all day. When the level goes down he "tops it off" and if it gets cold he warms it up via microwave. My coffee has never lasted that long but he seems happy with it. It tastes better doing that with better coffee but I still do not do that. I drink my coffee then just pour a new cup (or glass if it is iced coffee). Maybe it is just a midwest thing. I know up here in diners the waitresses will come by the table and offer to top it off.   Does anyone else do the top off or are you more like me in that you will finish one cup before starting a new one? I do not care if the coffee gets cold - I prefer iced anyway. ;) I use a percolator to make the coffee then transfer it into a thermal carafe so it is still warm and airtight.