The 75-year-old probably does more in a day than most employed people without receiving a cent.
The Otago and New Zealand swimming stalwart began volunteering her services as a starter, timekeeper and local referee in the early 1970s, when a doctor recommended her son Gregor begin swimming to help with his bronchitis.
A decade later he was swimming the 200m butterfly and the 100m freestyle for New Zealand at the now defunct New Zealand Games, as his mother sat poolside, doing her bit.
He has since moved on from the pool, but McFarlane has not.
She knows better than most that volunteers sustain sport at the junior level, and she still mainly pays her own way to officiate at meets around the country.
Daphne Loader, whose son Danyon swam countless laps under McFarlane's watchful eye at Moana Pool, said McFarlane was always willing and able to help wherever she could.
The woman herself deflected the question about why she continued by posing one of her own.
"Why not? I've made a lot of great friends through swimming, both here and overseas."
She credits the late Ian Chadwick with mentoring her during her early days.
"He was one of life's gentlemen. Anything I got stuck with, I asked Ian."
Swimming, though, is just the beginning of McFarlane's volunteer efforts.
She recently celebrated her 75th birthday in Mombasa, Kenya, where she spent three weeks teaching English at the Aga Khan Academy in Kizinga.
It was her third time visiting the continent after earlier visits to meet the children she and husband Paddy sponsor in Malawi and Mali, and she has vowed to go back.
The former St Clair Primary School teacher also takes a literacy programme at Otago Boys' High School on Thursdays, teaches English conversation at Otago Polytechnic on Mondays, and is heavily involved in both the Green Island and John McGlashan pipe bands.
Whispers persist she will be the next patron of Otago swimming, but McFarlane said she had not been formally approached about the role.
Either way, the licensed pilot intends to continue living life to the full.
"You've got to go and do it because you never know.
"I haven't got time to be a boring old fart."
There seems very little chance of that developing. Her mother remains self-sufficient in her Invercargill home at 94.
McFarlane, who has lost three sisters to cancer, recently asked her mother if she now qualified as her favourite child.
"Mary, don't kid yourself," came the reply.
Mary McFarlane
Pool queen
Age: 75
Sport: Swimming
Roles: President and committee member of the Otago Swimming Club, on the Kiwi Swimming Club committee since 1974, official New Zealand starter, timekeeper and judge, and manager of numerous swimming teams.
