Keeping it around, I learn what is or isn't working at a glance by skimming over these repeats hours to months later. I'll often copy-paste the same to-do list when I didn't finish it that day, or 'redraft' the same thought an hour after I first logged it, with some elaborations. My logs are not just what happened but also what I wanted to happen on that date.
I have a generic diary text file that contains catch-all musings, but I am increasingly using different logs for different tasks since I don't currently face a lot of time contention that would necessitate a detailed calendar.
The format changes with the context: I have a different logging strategy for fitness(Fitnotes app, and since I was just gifted one this past week, a Fitbit) from the logging used for programming notes(repetitive short block comments with date, time, and sometimes title). The key for me is that it's not about the format. Not parent, but I can chime in with my current system: Simple logs that I can search and copy.
