Recently, I was working on a refactoring project. The project involved more than 20 changes, but there were only three persons involved in the design, in addition, the three of us are not very familiar with the system. During the design process, we adopt the detailed design of the more than 20 Modification points for further development, however, in the actual design process, it was found that the team had to go through a long and continuous process only after more than 10 days of discussion in the early stage due to fewer personnel and demands, as a result, the team's work efficiency is getting lower and worse. Therefore, we feel that we should select the project scale based on the team scale in future development. For large projects, we can consider developing them in stages, to maintain the tasks at each stage is a task that can be easily completed by the team. This is what the ancients have said, and it is the truth that everything is exhausted, if a person spends too much time on one thing, his work efficiency will be seriously affected. For large projects, we should adopt a solution that focuses on the advantages of each other to ensure that the team is always in a more efficient state, once a task lasts for too long, you should switch your work items. The core of the top ten military principles summarized by Lao Mao is to concentrate on the advantageous forces to fight the annihilation war.