Testability {#4} influences the ease of:

• Testing and conformance to legal, industry and other required standards
• Verifying the design and validating the product
• Selecting and validating components and materials
• Negotiating with suppliers
• Validating reliability requirements
• Production, service, installation, calibration and inspection
• Acquiring or constructing test equipment
• Selecting production facilities
• Design of all test processes: development, production, QA/QC, regulatory, etc.
• Training: personnel, equipment, facilities
• Customer support: repair, upgrades, bug corrections
• Component and material selection
• Response and cycle times
• End-of-Life requirements and procedures

For example, an easily tested product can lower the development testing, production testing and support testing costs, sometimes dramatically.