High customer concentration is a common risk—if a major customer reduces orders or switches suppliers, the entire business suffers. You don't need to wait for a completely new product or distribution channel to begin diversifying. Instead, you can use a "market testing" approach with existing products, conducting small-scale trials targeting new customer groups. The concrete method is to first define a new customer segment (for example, buyers in different regions or of different sizes), design a simplified quotation and communication process for them, and observe the inquiry behavior and acceptance level of this group. Throughout the process, document every interaction so test results can be reviewed and replicated rather than dependent on one salesperson's personal relationships. This way, if a senior employee leaves, the accumulated market experience won't be lost with them.