They have seen golfing prodigies stumble, they have seen players' priorities change, they understand the rigours. But they love what Ko is doing now.
They both talk about the quality of her swing which has been honed by relentless time on the practice fairway but are more impressed by her focus and application, the sort of qualities which separate the very good from the best.
"She works hard, she knows what that involves and you have to have that love, thirst and work ethic for what she has chosen," said McGuire.
"When you see a young kid with that, then they have the chance to go on and succeed ... It is not just on natural ability.
"She knows it takes a lot of effort, a lot of time and commitment and she knows that at a young level. Because she is achieving at such a young age, she is either going to continue with her love for the game and all that she enjoys about it or she could peter out.
"There is no way to tell. Over the next three years is the time when she has to figure out whether she wants to keep going."
McGuire points to Michelle Wie, someone she felt was never managed properly and is still struggling.
"I think it is a good thing that Lydia waits. I think it is good to have an age limit before she can think about turning professional. She needs to have a life, have an education because there is always the worry about injury.
"You don't want her to miss out on her childhood either, you only get it once.
"Money does not come into it. I never turned pro to make money. I wanted to play and see how good I could get, if I could cut it and compete at that level and the money is a byproduct of doing something that you love."
Lister often played some holes on a Sunday with Ko before she blew out 10 birthday candles.
"I saw my role as grandfatherly, to help her understand course management and grow her as a person while it remained fun for her. That is the key, it has to remain fun and she has a fantastic sense of humour and lots of imagination."
Lister thought an aunt probably gave Ko her initial love of golf while she was also close to Sharon Ahn and her Korean family who ran the driving range at Takapuna.
"All kids these days can hit balls but they don't end up as an incredibly dedicated, hardworking gifted 14-year-old, winning professional tournaments. I can't believe that at her age but I can understand her love and joy of the game."
Lister also rates Ko's mental edge as her greatest golf weapon.
"Few people succeed initially, it is a learning process, and she is a great learner.
"Little stands out about her game but it is obvious the repetition of practice helps but they are also big into fitness, diet and strengthening.
"Lydia still surprises me and these women pros she plays against can't believe it either, that a 14-year-old is whipping them."
Lister reckoned he played seven rounds with Ko before he saw her "miss" a shot. She had a gift for golf but welded a tough practice ethic to the game she loved.
"You can always say she is fantastic at 14 but who knows what or how she will be going this time next year. There are thousands of kids in golf with talent but the way Lydia has progressed you would say the future is extremely bright."