I find I either do enough that I forget every little thing, or I do so little that I don't feel like getting on the computer to document it.
Today for example, I did a total reset of my RKL system, updated all modules to latest firmware, added the RKM-NET module and got that working (headache at first, easy once I figured out what I needed to do).
Tomorrow I'm doing a reset of the sump area. Stand alone fuge is coming out, CA reactor and kalk reactor are all going INSIDE the stand, gonna rework some plumbing, maybe...etc.
Other days, I just feed. I'm still not working on a "set" work schedule, so it's not easy to plan water changes and stuff, I just start mixing water, and when I get to it, I do it.
I even used to keep an excel chart for my VSV and Vitamin C dosing, but that fell by the wayside with school this past semester and when I figured out my good maintenance doses.