The concrete examples of what worked and what didn't - "any of us that pretend it worked all the time are kidding ourselves really" - provide context for his Institute of Directors audiences.
It's training that wasn't available when he pulled up a chair around the board table; when if you were lucky you learnt from the best, and if you weren't you risked ending up on the wrong side of governance law.
"I think today one of the things that we can do is try and make sure people coming into the governance profession do know what they're about, do know what best practice looks like and are much less likely to end up in those spaces that you don't want to be in."
He puts his own relatively easy transition from management into governance - a fulltime job since 1994 - down to his background as an engineer.
"You don't need to ask an engineer: why do we need to plan this?" says Rhoades.
"We already know; if it's not on a plan it's not going to be built."
Governance, he says, is setting out the purpose and strategic direction of the organisation - which is worked into management plans - then monitoring and chasing management along in that direction.
"I do think the vast majority of chief executives are up to their arses in alligators in their businesses."
The tide of emails, paper, appointments and phone calls that fill an executive's day is a "cloying swamp", he says.
"Lift[ing] those chief executives out of that swamp on a regular basis by facing them with questions about progress against your strategic objectives is, I believe, the fundamental purpose for having a board.
"The challenge with many New Zealand company boards that I've seen is many are far too willing to leap into the swamp along with the executive."
Rhoades says the groups he talks to are all too aware that boards should be setting strategic direction. However, what they see in practice are directors mired in monitoring management performance.
Risk and compliance have justifiably become a major part of the governance landscape over the past decade, but that has had the effect of dragging directors into the operational arena.
"There's a natural tension between the board pulling the company forward and striving for performance versus holding them back, if you like, and trying to achieve compliance."
In a recent Institute of Directors survey, about two-thirds of chief executives questioned said the board was a brake on the business rather than an accelerator, he says.
"That's concerning because it does mean that the boards are not in the right place, so we just have to make sure we keep boards out in front."
There's a natural tension between the board pulling the company forward and striving for performance versus holding them back, if you like, and trying to achieve compliance.
Rhoades says directors add value by bringing an external perspective to help those "that are too close to the weeds" - something that is most needed among the small- to medium-sized companies which make up the majority of New Zealand businesses.
But roles on an SME board are potentially the most risky for directors because these companies often don't have the resources to properly manage things such as health and safety, he says.
"As a professional director working in the SME space, you may well be the last person who is told if there is a problem, so you need to exercise care, but all of those smaller companies - and I've worked with a number of them - I've seen them losing a lot of value or leaving a lot of value behind because they haven't had an external perspective to help them think, for example, about exit strategies or funding strategies for growth and other key areas that they will face."
Rhoades is now winding down his governance commitments, including retiring from fronting courses for the Institute of Directors.
He says he plans to revert to being the engineer he was never able to be, walking past the door of his office in favour of the workshop. "My project list will see me out, I've no doubt about that."
And his six grandchildren can expect to see more of him too. "When a smiling 3-year-old face pokes itself around the door of my office, I want to be able to go on the floor and play rather than have to turn away and do the emails that I'm working on, and I look forward to that opportunity."
