Vernon Cook gives some words of advice to his boss Brian Davis
"Turn up, keep up and shut up" used to be the mantra for a caddie.
But a modern-day "cad" very much forms a team with the player he works for.
We asked top bag man Vernon Cook, who works for European and US Tour pro Brian Davis, to describe a day at the Open.
0445: Alarm clock goes. This is it then, first day of the Open. I'm up and out in a flash. It's a 20 minute walk to the course from my rented house in St Andrews. There are five of us - Lee Westwood's man, Nick Price's man, David Frost's guy and Ben Curtis' caddie.
0515: Arrive to walk the course and check the pin positions, just to see where they are in relation to the trouble. Wasn't the first here, won't be the last. Most cads will do this, even the guys on the late shift. They'll jog round and go back to bed.
0615: Meet Brian in the locker room. He's staying in Dundee and driving in, about half an hour. Go to practice putting green by the first tee. Just a quick 20 minutes, checking the stroke, trying to get a feel for the pace. Still nothing to eat but I'm not much of a breakfaster. Wouldn't mind a cup of tea, though. But nothing for us here at this time of the day. We're really well looked after. Not!
0650: Head to range for Brian to warm up his swing. He goes through the bag, from wedge to driver. Maybe a little go in the bunker. My job is just to keep an eye on his swing. The clubs are all OK because we clean them as we go.
0720: Back to the putting green for a final hit. Check we've got 14 clubs, get up a back-up yardage sheet.
0737: "On the tee from England, Brian Davis." We're looking forward to it, not nervous. For his sake I try to look calm, putting on my poker face. No point in both of us being nervous. Look at the wind and decide on first club. Stand back. We're off.
0800: Walk off the first green with a double bogey after going into the water. No need to say much. Just have to get on with it. One of the main parts of the job is man-management - judging your man's mood and knowing when and when not to say something. Have been with Brian for nine years so pretty in tune.
0810: See the giant leaderboard with Nicklaus and Watson, in the group behind us, at one under, and Donald level par. Brings a smile to the face. Nice too see the old boys getting one over on the youngsters.
0900: Four over after five. Tell ourselves we have just got to hang in there and get a couple back. It's a major, anything can happen. Mood never too dark.
1030: Birdie on 12 gets us back to two over but a bogey at 13 isn't so much fun after we find the Coffins bunkers. Hindsight is a great thing but probably should have gone with driver not three wood.
1100: Look up at the leaderboard and see Tiger Woods at seven under. OK, here we go again.
1220: Finish with a birdie to make ourselves feel better. Hang around the 18th to get Jack to sign a couple of his fivers and some replica pin flags for a friend's charity back home in Worthing. Being in the group ahead gives us the best seat in the house for the old man's send off. Brian goes off for lunch and I head into town to get a paper and have a sandwich.
1330: Meet up with the boss again on the green. Spending a lot of time here. He tries a couple of different putters, I take some photos of his posture with a phone camera, offer advice and fetch the balls. Wouldn't mind an ice cream.
1445: Back to the range. Work on swing basics but left-to-right wind doesn't help.
1530: More putting duties.
1645: Arrange next day meet-up. Get bag ready with extra balls, waterproofs, clean towel, tees and so on. Anything to save time the next day.
1715: Free at last. Stroll up to the Dunvegan pub for a Guinness. No-one around so head home for a lie down. It's been a long day already. Read a bit more of my book Angels and Demons by Dan Brown.
1850: Back into town to meet a couple of friends - Soren Hansen's caddie Adam Drummond and Duncan, who works for Peter Hanson.
1915: Quick pint and then try to find somewhere for dinner. Bit of a nightmare, everywhere is so rammed.
2130: Eventually find a pizzeria that will have us.
2300: Back in my pit - honest! At 46 it's not like the old days. And I've got pins to look at in the morning.