I agree wholeheartedly. "Unexplained changes" are the predictors of issues. I have written somewhere in these hallowed pages that I keep a logbook with each vehicle, recording everything that goes on, comes off, goes in, and how far. Plus, when any and all servicing is performed, the date and the odo reading. New noises & vibrations are also noted for posterity.
Paper & pen are cheap as compared to major maintenance.
I do not expect everyone to understand why I do this, but if you have ever maintained a helicopter, or a fleet of 16 helicopters, documenting these things always helps - even if to provide a benchmark of perfection.
Cheers,
Steve