I have a couple problems with this. The first is that the feature would require everyone to have all the information available (when they filled up, etc.) and they'd have to consistently submit accurate data. Losing one receipt with a date will mess everything up. Secondly, the mileage database is simple and intuitive. The more features I add and the busier it gets, the less people who are going to want to participate. 90% of people don't really need/want all the bells and whistles.

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