Be aware of the fourth time assignment

I read somewhere about Sweden's 1967's shift in left-hand driving to right-hand driving. On the Monday following the shift, there were less traffic accidents, 125 reported traffic accidents, compared with a range of 130 to 198 for previous Mondays. Most had anticipated more traffic accidents. It is likely that the higher attention by drivers contributed to the lower number of accidents.

When my daughter learned how to cycle at the age of 4, I was very careful. When we cycled I cycled real close to her and held her neck near traffic. So she learned to cycle steadily. After roughly 6 months, I slowly started to pay less attention to her and got more confidence in her skills. Then, once when we were very near home she rode her bike behind me (normally in front of me), and a man came from the side and ran into her. It wasn't too bad, but she had some wounds because she fell with her face on the steer of the cycle.

I think knowledge workers may be at their best when they do a similar job for roughly for the third time. The first two times they gain experience. The third time is the best, small mistakes from the first times can be corrected. The fourth time assignment there is a risk that you loose attention and make unnecessary mistakes. Of course there may be individual difference and task differences. And you can argue that for knowledge workers, every assignment is unique, so it's hard to have a really similar job.

I started thinking about this when I thought about learning from mistakes. Somehow I don't believe in learning from mistakes. Most of the times, we know the mistakes but there are other reasons for underperformance like lack of attention.

What do you think? Do you recognise this? Or do real masters never loose their attention?