Not trying to sound like your nanny, but you're not doing your fuel pump any favors running less than a 1/4 tank. Nearly every vehicle has the electric fuel pump in the tank these days, and having less than a 1/4 tank makes them run a lot hotter...thus shortening their lifespan. And not only are they fairly expensive, they suck to replace !!
I never knew that. Thanks, T^2.