Billy Harmon surveyed the scene at the U.S. Senior Open. “Look up and down the range here,” Harmon said Saturday afternoon at the Warren Golf Course at Notre Dame. “What do you see?”

The youngest of the famous Harmon brothers – all of whom are  instructors – was making a point with his interrogative statement. 

The answer is what you didn’t see. No Trackmans. No gadgets.

And no instructors.

Players competing this week in the 40th U.S. Senior Open Championship are in the do-it-yourself stage of their careers. They no longer hit the ball as far as they once did, and they certainly have their struggles with their golf swings. They are not immune to patches of inconsistency and the itinerant frustrations of the game.

As Tom Watson, who long has owned one of golf’s most repeatable and trusted swings, said after an extended range session on the eve of the championship, “you never stop working on golf.”

But for the most part, the work they do is alone. The fixes and adjustments are in their heads. They know their swings well enough – and their swings are now so ingrained in their muscles – that they are seldom searching for answers to any issues that arise. They simply flip through their memory banks, apply the smallest tweak here or there, and then they go play.

Harmon, who this week is on the bag of Jay Haas, for whom he has caddied off and on since 1978, loves this. He loves seeing the quirks, the signature moves of the 50-and-over set. He and his brothers were taught the basics of teaching by their father, Claude, the legendary head professional at Winged Foot – site of the 2020 U.S. Open. The foremost lesson they received, Harmon said, was “when you’re working with a good player, figure out why their swings work, not what’s wrong with them.”

By this point, most of the best senior golfers have figured out what works.

“These guys are at a point in their careers where they really don’t lose their swings,” said Harmon, who has taught Haas and Haas’s son, Bill, a six-time winner on the PGA Tour and the 2011 FedEx Cup champion. “They know their swings so it’s easier to self-correct. Most of them started playing before the information age, all the high-tech stuff that’s out there now. They don’t have all this information that a lot of times, I think, causes confusion.

“I think it’s important to note,” he added, “that they haven’t contracted their swings out to somebody else. They’re soloists. And that makes them very effective players. They are simply more self-sufficient.”

Even though he is an instructor, he does very little to help Haas on the course, other than his usual caddie duties. He might, at times, make a suggestion for a refinement in Haas’s swing, but he only offers an opinion if it’s solicited. “I work as his caddie,” said Harmon, 67. “Other than that, I’m a good set of eyes more than anything.”

“It’s just a comfort having someone who is so familiar with my game by my side,” Haas said. “We have a long history together, and it’s nice to have him out here.”

Harmon, who was diagnosed with tongue cancer in 2016, said that players’ swings evolve naturally with age. “Their bodies can’t quite move the way they used to, but they keep the same basic principles.”

John Cook, a former U.S. Amateur champion who primarily works in television for Golf Channel, opened the championship Thursday with an even-par 70, but he missed the cut by a stroke after second-round 72. He seldom practices, but he does try to play at least two 18-hole rounds a week. He proved that he still had enough game to decently acquit himself.

“I don’t think I’ve done anything different with my swing in 40 years,” said the 11-time PGA Tour winner. “I might not be as consistent, and I don’t score quite as well because I don’t play a lot. But at this stage I know what to do.”

Winner of the 1982 U.S. Open among eight major titles, Watson, 69, said the game “became easy for me” when he made one adjustment to his swing. “I found in 1994 if I keep my shoulders on a more level plane on the downswing … my ball flight came down a little bit, but I hit the ball so much straighter,” he said. “The game got easy – literally got easy, for a long period of time.”

And with that swing he nearly won the 2009 Open Championship at Turnberry at the age of 59.

“It’s all about getting the clubface square at impact on the right path,” Harmon said. “These are clubface and path guys. They look at the ball flight and divots and that’s all they care about. Seems to be working.”

Harmon has a strong idea about what often doesn’t work for younger players. They don’t own their swings. There is too much information at their disposal. And he thinks many instructors stray from his father’s basic principle of figuring out what works for them and why it works.

“Anyone who wants to talk about what’s wrong with Rory McIlroy’s swing when he’s fifth in the world doesn’t get it,” he said. “Are you kidding me?

“I’m always fascinated by this effort young players have to get to the next level,” Harmon added. “These guys (senior players) aren’t trying to do that. They’re trying to play golf and compete. No one is trying to coach the genius out of them. They’re under-coached, and that’s a good thing. I love watching them.”

Dave Shedloski is an Ohio-based writer whose work appears regularly on USGA digital channels.