I know everyone does this differently, but I track my mileage by resetting trip 2 each time I get a fill up. Then I have the overall MPG on trip 1 and this tank on trip 2. Discovered on my 2016 FFH that at 10K, my trip 1 automatically reset itself to zero. WTF! Why does it do that?? Well, anyway, at the 10K mark I was at 45mpg. Now at least I can add 10K to whatever the mileage is now on trip 1 and do some weighted averaging to compute overall MPG. Life is so complicated!!