When adding a new feature to an existing software product, many programmers and designers just sit down and create the look-and-feel from scratch. This is a mistake, since it leads to user interfaces that have little in common with the rest of the product. A much better approach is to study the existing features in your product, and use the same styles and design patterns when creating the new feature. This approach will save you development time, make testing easier, and ultimately provides a better end-user experience. Since the new feature will already look familiar to customers, they’ll find it easier to learn and use.