I think its just the difference between people who buy gas in the morning, leaving the house, or on the evening on the way home.
My wife definitely is in the "I'll get gas nex time I leave the house" camp, while I am in the "I better fill up on the way home while I have a few extra minutes because who knows how late I may be running tomorrow" camp.
Of course, on the weekends, we always drive her truck (do you call an Explorer a truck?) because its setup better to haul the kids, and invariably, first thing we do is stop and I get out and pump gas for her.
On another subject, its always good to drive the wife's vehicle once in a while. You always notice things she would never mention. Mostly its simple stuff like keeping air in the tires, noticing the oil hasn't been changed in 7000 miles, or its time for some new wiper blades. Sometimes its big stuff like that grinding noise in the rear axle that I knew wasn't right that she said she had been ignoring for months. Lucky I noticed it before the warranty expired. It turned out to be a known problem with the limited slip that would have cost thousands to fix if the odometer had happened to have ticked over 30,000.
- Rick