I keep logs on all four of our horses even for the short time we've had them. My wife even keeps a daily entry on progress that we and each horse make to keep track of what is working and what isn't.
I have built a few heavily modified off-road vehicles for trail riding and got in the habit of keeping records to know what vehicle I got parts off of to put on each one I was building..They were what some call a Frankenstein with parts from so many different kinds of vehicles to make it do what I wanted to do.
I am building a 94 Jeep Wrangler now that has parts from 9 different kinds of vehicles. Lol