I inherited a huge folder of stuff when I bought my car. I read it once and it's sat on a shelf ever since.
Not bothered logging anything I've done or keeping any receipts or stuff. Can't see the point. I do have a couple of Google docs - one covers the Service schedule - I put in the mileage I did a task (oil change, greaseing etc) and then the mileage when I need to do it again. Also things like ignition timing, valve clearances, plug gap info.
The other is a 'To Do' list where I jot down jobs I have planned (including parts required and how much I need to save up!). All gets deleted once complete.
I have a whiteboard in the shed, where I jot random thoughts and a note book where I draw/design/plan stuff for cars and bikes. Gets chucked when full and replaced with a new one.
