I know/work with a number of Engineer/Machinist types and you just have to let them do their thing.
Recently one of them was getting some brake work done to his truck. I was like while they are in their you may as well have them do the rotors so you wont get stuck on labor twice since they looked as they too would need to be replaced within the next 10,000 miles or so. He shot me the look and I got the "I am an engineer speech" and how he could not replace a part that still had useful life. I am a business man and it is all about the CBA. 😀