Using Excel and LINE for record-keeping causes errors even in daily operations, and the problems become more pronounced during market testing. The essence of testing is to "collect data, compare results, and make decisions." But if data is scattered across different people's LINE conversations and multiple versions of Excel files, it becomes difficult to confirm which data corresponds to which test plan, or which customer feedback was directed at which price version. This leads to "seeing lots of numbers but not knowing what they mean." It's recommended to establish a centralized recording mechanism before testing starts, ensuring that inquiry sources, quotation versions, and customer responses are traceable. Centralize quotation management and exchanges in a single system, keeping a record each time you send something. When you need to compare two versions, you can directly view the differences. This is the most basic condition for making test data effective.