[Diesel_Dave]

To each his own, but I run mine down to almost completely empty. This is for three reasons.

1) More accurate mpg numbers
2) It's a game with myself to see how many miles I can get out of a tank
3) I have a tank that nominally holds 34 gallons. The grocery store I use (Kroger) gives me a discount on one fill up per month up to 35 gallons. If I run till empty I can go all month on one tank and 35 gallons fills me up into the filler neck. In the last 7 months I've driven 7,853 miles on 7 tanks.

I've never run the truck out of fuel, although once I had it in the shop and they ran it out while test driving it. That's not something I care to repeat--every so often some air would hit the injectors and it would stumble & studder. It took a week or two for the intermittent symptoms to go away.