I've been working on one of my kung fu forms consistently for the last few weeks. At first I was a little sloppy from not having practiced it in a long time. I worked on it a little every day and got used to the movements again, gradually making it flow better and with greater power.
After about a week of this, I received a challenge to make a video of myself performing. I recorded my form in a nearby field and had a quick look. It wasn't pretty. I rushed sections of the form and lost my balance. My hands were all over the place in some of the techniques and the alignment of my stances made power delivery impossible in a few places.
Disappointed with myself, I had another go. This time I took care not to rush and to concentrate on the movements and applications of the techniques. The resulting video was much better. Everything was much more crisp and tidy. The remaining errors are indicative of flaws in my form rather than just bad habits and sloppy performance. They will take more considered practice to correct, but it is at least a lot easier to work on the problems when you are aware of what they are.
There are lessons to be learned here. Practising the same thing without feedback entrenches bad habits and allows improvement to slow to a halt. In the absense of an instructor to make corrections, video and self criticism can provide enough feedback to keep you honest and maintain your level of performance. It can also help to highlight any other flaws if you know what you are looking for. Video is good. I exspect it can be used in other sports and activities to hasten improvement and prevent bad habits from creeping in.