The essence of agile development is to respond quickly.
What is the response? Corresponding changes.
Who change? Demand changes.
If we can re-acquire demand from users every other second, then analyze, design, encoding, and test, then we will not complain that users' needs always change. Because in this second period, the user's demand has no change. But obviously, this is impossible.
There are two places where it is impossible, one is that we cannot re-acquire a demand every second. Second, we cannot re-analyze the needs of users every time.
But we can find a relatively balanced time period and demand block, although it is not a perfect balance. How long is the time period? Depending on the rate of changes in user demand. The faster demand changes, the higher the frequency of the acquired. Every time you analyze and design how much demand? This depends on how much time we have and our work efficiency. (I am not particularly affirmation for this sentence).
Why do you need to refactor? Because it will make the code more flexible, there is a better reaction ability.
Why do you want to decline the code? Because the dead will never make a response.
