Malcolm and Brenda Yorston have barely slept in for 37 years.
That was when they took on their first foster child, who was aged 7.
"We've never stopped," Brenda said. "We've just carried on and on."
The Glenfield couple have taken in more than 100 children from state care over four decades, making them possibly the busiest foster parents in the country.
"How can you stop when there are not enough caregivers and more kids coming into care?" Brenda said.
As of June last year, there were 6350 children in state care - up from 5700 the previous year. There are roughly half that number of approved caregivers, and authorities are desperately seeking more.
The shortage is likely to be tested further when reforms come into force in July, allowing foster children to get support up until age 21, rather than 18.
Malcolm, 72, and Brenda, 65, have mostly taken on newborn babies. They housed a teenage girl once, and, because they don't do things by halves, they housed her boyfriend too.
"When we found out he was sleeping in the paddock near the house, with a rugby ball for a pillow, well, we had to take him in."
But newborns are preferred because they are easier to manage.
"Who knows how many nappies we've done," said Malcolm, who still works in the car importing business. "Tens of thousands. Hundreds of thousands."
The children are removed from abusive or negligent parents, often at birth, and delivered straight from the hospital to the Yorston's home. All removals must first be approved by the Family Court, which needs to be shown evidence or harm or risk of harm.
Pointing to a heaving photo album, Brenda points out one of the worst cases: "These two were thrown against a wall and had pillows placed over their faces."
At the moment, they are caring for two boys under 1 and an 8-year-old girl, who they have adopted. They have five children of their own.
Many of the foster children arrive with no experience of positive family life.
When the Yorstons were looking after an 8-year-old boy, the washing machine broke down and Malcolm joked to the child that he would have to wear his underwear inside-out the next day. The boy took it literally.
"They just haven't known humour," Malcolm said. "They don't quite get it."
Brenda added: "Once they get into care and realise there's a meal coming, you don't have to steal food, if you wet the bed you can put your sheets out without getting told off, there's no hitting, they soon settle down and fit into your family with the other kids."
The children stay at their home for months or years, depending on whether there is a stable, permanent home for them to transfer to. They describe their relationship as more like grandparents than parents - partly because one day they'll have let go of them.
"We treat them like our children but we know they're not our children. We always keep that. And a lot of the time I don't want to intrude in their [new] family. I want the kids to bond into their family."
Some changes over the past 40 years have made life easier. Facebook has helped them keep in touch with the children, some of whom have gone on to become high achievers in business overseas.
There have been a few "hiccups" but most of their foster kids have gone on to thrive.
But the couple worry for the sector as whole. The children being removed from families have increasingly complex problems, and drug and alcohol cases are becoming more common.
Social workers are stretched by 35 to 40 simultaneous cases. "They only have time to put out forest fires," said Malcolm.
The labour shortages mean they are not willing to retire yet.
"Down the line we'll stop," Brenda said. "That part I find really hard to say ... because I enjoy it so much.
"If we can give these kids a concrete foundation for however many months or years of their lives, at the end they are going to become good citizens. They are going to be part of the world that our grandchildren are growing up into."
Malcolm: "And the kids keep you going. I'm only 72. And they say 70 is the new 40."