I feel like the point that verification/validation will not always pass needs to be brought up more. Companies need to keep in mind that the verification and validation steps will not pass, so that if they fail the timeline is not drastically affected. Failing either can set a project back months if not longer. As to the specific when should either start it’s hard to say. Some need to start at the beginning, other needs to start after the project gets of it’s feet. However, it is probable that the sooner these steps are started the better the chance of the project succeeding and doing so on time.