My brain.
I'm not sure if I've kept a paper record on the mustang. On my old F-150 I wrote it in the back of the owner manual, there were a couple of blank pages.
Side note: your 94 owners manual looks a lot different than min... Can vs US thing?
lol I never knew that existed! I just use a spreadsheet if I record it at all
My brain. My car can't follow the factory schedule.
This.
I don't record anything & keep track of things just fine.
Receipts are always a plus when re-selling a car.
I don't go up on price If a guy hands me a book of receipts for oil, belts, ......