I’d love to be able to make notes during a workout. For example, ‘gel here’ or ‘this one felt better’ or ‘had to pause to answer the door’. When I go back to look at a past workout, or even tracking progress during a long workout, it would be great to have that sort of detail.
Post workout just make notes. Once you complete the workout you’re in a better position to analyze your effort, if you lacked fueling, adjusted intensity, etc. You can additionally look at HR and cadence over the workout and consider your RPE.
My post workout notes look more like novels and it’s very interesting too look back on workouts I did 6 months ago to compare what I said then.