The slick brochure promises every feature you can imagine, and the sales rep assures you that his package will do just what your users want. But that's what the other vendor's sales rep said, too. Sound familiar? Karl Wiegers recommends several requirements development practices that can help you select the right commercial package solution. Key practices include identifying user classes, defining their use cases, creating test cases from the high-priority use cases, documenting pertinent business rules, and exploring the users' performance goals and other quality attributes.