This is the kind of app that makes having a smart phone worth it. If you're the type who likes keeping track of every tank of gas that goes in your car, Acar has extensive graphs and charts to keep track of mileage and price. If you're bad at keeping track of vehicle maintenance and repairs, it has reminders and you can easily look up your last oil change. Whenever you fill up your car or perform vehicle maintenance you simply fill out the customizable fields. Your info is available in several forms including charts and statistics, and even csv export. You can also setup reminders for maintenance items, and everything is customizable, from the fields available to the type of repairs you can enter. I've been using this app to keep track of gas mileage and vehicle maintenance for the last few months and have had few problems. A big change came in 2.0 included a nicer interface and home screen, but does make it a little harder to see the latest gas mileage after you enter a tank. It is free with no ads, but the catch is that you need to donate to enable backups. This means you can try the full app without commiting to paying anything. Backup and restore options are extensive and worth it if you plan on using the app long term. The one problem I did encounter is when my phone, a Droid Eris, was upgraded from Android 1.5 to 2.1; the app force closes when upgrading the OS from 1.5. This is apparently an Android bug and there is not Acar's fault. Fortunately I had a backup I could restore from, so keep this in mind if your phone has 1.5 on it. Despite the small glitch I give this app a 5 star review, since it is just what I was looking for and works great.