For every ride/workout that is recorded in Training Peaks (which is all of them), I record my fatigue level after the ride, and the RPE of the ride. I also write notes as appropriate about hydration, fueling, what went right, what can be improved, external factors that might have affected performance, etc.
I can also bring up previous times I did the ride beforehand to view my notes, or afterward to compare performances.
It also records peak performances.