I've kept a training notebook for quite a number of years, and still do.
Usually writing down poundage/sets/reps after that exercise, or workout, is completed. Interesting to see the pattern of strong days compared to days of average, to less than average, performances in workouts. Also the mood and how that can affect a workout. I learn that there is a different pattern, from extra poor to excellent workout days..for me anyway.
Thank you for sharing your experience