Gas: How low do you let it go before filling up

[CtrlAltDl]

By golly! What a kick in the head! I rode a bit deep into the F-trip yesterday (4th nice day this year, the weatherman said) and got a shock at the gas station: over $15 for nearly 4 gallons.

Yea, but it's always fun filling up next to the guy in the V-10 Ford F350 and screaming "fifteen dollars!" and then watching his reaction after he slides his card the second time because he hit the $100 limit on the pump. LOL