Chips comprising 500,000 logic elements are the silicon brains inside cell phones, MP3 players, computer printers and peripherals, digital television sets, medical imaging systems, components used in transportation safety and comfort, and even building management systems.
The best way to achieve high confidence is to leverage the pre-silicon verification work - which can comprise as much as 30% of the overall cost of the implementation - and use that knowledge in the post-silicon system.