When training in the martial arts it can sometime be hard to see progress and improvement over time.
This is one of the primary reasons to train under an instructor or as part of a group- they can see your progress, help adjust it, and keep the momentum going.
One of the recommendations that is made, is to video yourself training once a year, and after that put it away till next year.
Ukemi, kamae, san shin no kata, and kihon happo all make great movement drills to video.
Looking back, not so much at corrections to be made, but at the progress one has made over the years- a good medium to see it and keep motivated in training.