I try to keep maintenance records but my Jeep is dealer maintained (warranty) so they have everything on file. My Ram work truck I do at home...and there's sharpie under the hood like "H2O pump and belt 268,419", "GD Fuel Pump 212,870", and "South Bend Clutch 252,850". I also track pads/rotors/tires the same way on that one. That way, I can't lose the book! My Daytona and the minivan "toy cars", I track my LOFs the same way - sharpie on the core support, miles/date. Brakleen (or hair spray - try it!) takes it off for the new one. I don't worry so much about intervals for brakes and tires for them since they get used relatively little and are usually done on the date system as opposed to mileage.
Motorcycles, everything gets done at 5k intervals (engine oil, primary/trans oil). Tires and brakes when they wear out. They are dirt-simple to maintain. I track their MPG mentally, just out of habit (and to reduce the guilt of "playing" on the way to work - hey, I'm getting 48mpg...so what if I'm having more fun than that guy in the Prius??).
I do keep mileage logs for the cars and trucks though - date, $ per gallon, fillup amount, $ amount, EVIC mileage, hand-calculated mileage. Started that on the Ram (work truck, mileage deduction at the end of the year) and it grew from there as its a great way to help ID problems before you get stranded. Regular mileage, good. Sudden blips in mileage? No bueno. Find the source ASAP to prevent getting stuck.
The Charger? Has a book. Two, actually - the car-show binder with production info and original sales docs (original BoS, original title, broadcast sheet, etc), and the maintenance book. That one, I do for resale - if I ever need to buy a kidney or something, because that's about what it'll take to make me part with it!