Had a buddy ignore his timing belt change because his car "felt fine." Belt snapped two weeks later, wrecked the whole engine. Cost him four grand instead of the six hundred for the swap. His shop told him the interval was right in the book he never opened. That basic note taking is the difference between a cheap fix and a new car payment.
Seriously? It's just writing stuff in a book. Most things break when they feel like it anyway. Half the time you're just looking up what you did last time, which any shop already does. It's not a big fix, it's just basic note taking.