It's alot of time when you're wearing chicken plate, it's 130 degrees out, no air conditioning, and someone is trying to kill you while you fly just off the deck.
I've flown both sides- military, 135, and 121. The times can not be compared. Flying 8 hours a day 135 and especially 121 was a piece of cake. Press a button, "DING DONG". "Yes, may I please have a Diet Coke when you get a chance. Lots of ice. Thanks."
Military side, it went like this, "Hey chief, will you pass up another frozen liter of water so I can shove it under my chicken plate?" 15 minutes later it would be melted so I could drink it. 30 minutes later it was too warm to drink so I poured it down my flight suit. An 8 hour mission in the military kicked my butt by the end of my career and I had to take an 800mg Motrin before each one. I remember coming off one 9 hour mission after flying 5 days straight, barely able to get out of the aircraft, and being so happy that I had the next day off. The 21 year old WO1 copilot I was flying with came back from turning in our flight bag all giddy because we had just been put on the board for a mission the next day. I almost cried I was so tired.
But it does not make a difference with the FO in question. I don't care if he had 25,000 hours of combat heavy jet time. He's the FO. Captain asks you to do something by the book, you do it.