30 years ago? I talked to an project manager that designed and built factories. He said there were three kinds of engineers and techs he hired. Design, Construction/Shakedown and Maintenance. Design requires being creative and methodical. Construction and Shakedown requires the ability to gleefully beat chaos into submission. And Maintenance is the methodical following of rules and procedures. He hired three different groups for these tasks because they would go insane or be overwhelmed if they were doing the wrong job for their temperament and skills.