I also have never ran out of gas as well thankfully. I'm like Kalome as well, I'm always doing math in my head and especially if the tank is running low. Whatever the MFD says, I figure it's 2-3 mpg less and use 10 gallons as a base when I calculate. So when the tank is at half-full, if the MFD is showing for example 50mpg, I'd figure it would be around 47mpg and I would hit 470 miles at 10 gallons and calculate the remaining left from there. Before my last fill up 2 weeks ago, I decided to actually try and see how far I could go before I felt that I needed to fillup and logged 524 miles at 11.4 gallons miles which calculated to around 46mpg (MFD showed 48.6mpg). That's the most I ever filled up so far. I normally fill up about 9.5-10.5 gallons and I also never top off and always stop at the first click.