I never top mine off unless I am about to go on a long enough trip to burn a couple of gallons right away.
More often, it seems, I am continuously verifying the accuracy of the empty line on the gas gauge...
The trick is noticing at the very moment when the needle stops jiggling, knowing that I have 30 miles to find a gas station.
Win some lose some.
On the bright side, with these cool old trucks, people seem to be waiting in line to pull over to help you.
