I'm curious as to what people keep track of for their vehicles. For example, on all my vehicles I have a separate notebook and in it I have the full date and odometer reading of the event. Events are oil changes, air filter service, valve adjustments, wheel bearing lubrication...typical maintenance procedures. I also include other stuff like tire replacement (so I can see how long they last), clutch job, catalytic converter replacement, and other significant changes (one-touch sunroof install on the Jetta, 5-speed tranny for the Squareback, floorboards and heel-toe shifter for the Goldwing, etc.). Okay, so some of those items aren't necessarily "significant" but when some asks how long that one-touch has lasted or if the carbon fiber overlay on my bike has lasted more than 6 months I can tell them. I don't do tire rotations nor windshield wiper blade/fluid changes as those aren't critical/necessary data points in my opinion and are done on an as-needed basis. So, what do YOU log and how (Excel workbook, notebook, by memory or by the stack of receipts )? BTW, gas mileage I would not include. That should be its own little book.