For us cable certification is part of the project. It happens before drywall to catch any mistakes we made and after drywall to catch any mistakes they make.

In 20 years we have had maybe 3 projects with 1 bad wire each. Nothing we couldn't work around with extra cable or conduit. I have had plenty of situations where wires got cut short by drywall or cabinet installers. Having the two step testing covers us and we dont have to eat the additional expense of working around it.