HDL Code and FPGA Design Reviews and Auditing are often welcome or required :

• When an FPGA project is critical (or just important enough)
• When reliability is a key issue.
• When an FPGA fails to perform reliably in the field, or in a given production batch, or during reliablity tests.
• When the design is subcontracted, to verify that quality requirements are met.
• To get a slipping project back on tracks.
• To estimate early the complexity of a design.
• and many other circumstances …