Midwife Genny Healey locks in her holidays up to a year in advance, but when it comes to daily start and finish times, you'd have to ask the babies she delivers.
They're the ones who determine when she clocks on and off. Take the week before Christmas for example.
"On Monday, I got called at 5am and I got to bed just after 2am [the following morning]," says Ms Healey.
She delivered two babies in that working day of more than 21 hours, with help from her back-up who looked after one of the labouring women for four hours.
"On Tuesday I started work at 10am and finished about 10pm. On Wednesday I started at 10am and finished at 8pm. Thursday I started at 9.30am and finished at 6.30pm. Today [Friday] I started at 7am and I have no idea because I started an induction and she may not deliver till Sunday. I'm going out to do post-natal visits now."
She often doesn't get to bed until 3am and just as often that's when she gets up.
This topsy-turvy birthing business, where you hardly know if you're on night shift or day shift, can be tough on family life.
Ms Healey recalls her now-adult son, when he was about 11, saying to her at breakfast on the day of a school cross-country race: "'You'll miss it just like you did last year". I got cover for a couple of hours so I was late but I got there for the end of his race.
"I have the best job in the world. It's a miracle every day I work. It's the miracle of life. It's very special and it's just a privilege. The hours are a bit horrendous. That's the only drawback."
Ms Healey estimates she has delivered 3000 babies. A nurse and midwife, she began her career as a trainee at Christchurch Public Hospital in 1971. She has worked as a hospital midwife, a neonatal intensive care nurse, a volunteer in Papua New Guinea, and is now a lead maternity carer (LMC) midwife in North Shore/Orewa practice MotherWise Maternity.
She says her broad nursing base gives her the experience to notice more than just maternity issues with her patients and their families.
When she worked in South Auckland she sometimes referred people to budget advisory services and twice helped get families into houses through the organisation Habitat for Humanity.
"You're looking after a family as a whole. It's a good time to make lifestyle interventions, if you can get that family on the right track," says Ms Healey, whose patients have included women linked to gang members.
"That makes your job worthwhile when you feel you can make a difference in someone's life."
When not working, she likes to go fishing or gliding.
She compares gliding to her profession.
"You've got to be on the ball - it probably suits my personality. You dot your 'i's and cross your 't's.
"You're challenging yourself."