I use fuely to log my maintenance and mileage. It's free. You can store plenty of info in it and it's always available as long as I have my phone, which I always do. The costs aren't super accurate as I don't enter exact amounts for parts, only gas. I keep all the receipts if I need to get specific info. I have been meaning to do a detailed analysis of how much I've spent on it over the years, but I never seem to get around to it. Really don't want to know.