Reassessing, although very hard, is fundamental.
I find reassessment a brilliant challenge. Every time I question something about my class I start thinking about answers and solutions. Even if I don't reach a conclusion I always feel stronger and more prepared afterwards. It triggers new ideas that I want to try out. It keeps me on my toes. I can not find any good reason why not questioning the way you do things. Obviously, like anything, it is important to do it moderately.
The danger lays in what you do after questioning your class. I noticed that small changes are often the best way to go. It allows you to back track and take an other route if necessary. Sometimes not changing anything is the best option, you only need to try again and observe more. Some students need to hear things more than once, others simply need time.
It is also important to wonder if you have asked yourself the right question.
A student once shared with me the fact that she finds some of my exercises completely useless. If I had been inexperienced I would have simply stop doing these exercises or I would have tried to change them. That's why I think the question has to be carefully asked.
Where does the problem come from? The exercise itself or the fact that I haven't explained why we are doing it? If I have explained why we are doing it, then why did one of my student not get it?
It would be too simple to blame it on youth (she was a teenager), or lack of enthusiasm. It is important that all students understand the information.
In this case asking the right question is very important. You might find that the student wasn't paying attention or that your explanations weren't clear. It's necessary to check all options, always asking:
Could it come from me?
Some of the most interesting moments to question are the successful ones.
Why did it work?
Because once you know why something works then you can push it further and play with it. It is always a shame to find a class that works and keep teaching it the same way for the rest of your career. The students change enormously from one class to the next (age, level, abilities) so we can't teach them all the same way.
To conclude I would say that it is important not to take reassessment as a criticism but as a constructive challenge. At first I thought it was important to always have an answer but I now find that it is better to look for an answer by experimenting with new things. There is no rush to find a solution to a problem. The most important thing is to keep trying to find the solution.