Forget waiting until your kids are five to put them in school - education experts say the evidence backs waiting until they're as old as seven.
The Government announced on Wednesday it plans to drop cohort entry for four-year-olds, Prime Minister Jacinda Ardern saying it's "in the best interest of kids".
"The overwhelming feedback during the select committee process was that children shouldn't start school before they had turned five," added Education Minister Chris Hipkins.
Professor Welby Ings of AUT University says most kids aren't ready for school when they're four.
"There's some very good research saying even seven - places like Finland, that has an extremely good education system, kids are starting at seven," he told The AM Show on Thursday.
"Definitely there's research to say starting children before the age of five leads to problems."
A European study published in 2015 found delaying the start of formal school education from six to seven "virtually eliminated" inattentive and hyperactive behaviour a few years down the line.
"The research is showing when they start later, they do much better."
The problem, he says, is that many four- and five-year-old children haven't developed the "foundation skills" required to effectively learn in a school environment.
"Learning to estimate... our most fundamental mathematical skill; being able to communicate ideas, express ideas; being able to navigate relationships with people.
"If you don't have those, you're trying to build an education on a bad foundation.
"School essentially starts moving what's concrete, what's physical into what's abstract. Some kids can be very, very bright, but it doesn't mean they've got a good foundation."
So why did the previous Government want to make it so schools could start taking in children at four years of age? Prof Ings says it was "about appeasing a small group of people, I think it was about... playing with cosmetic change".
New Zealand Kindergarten chief executive Clare Wells said there was "no background work" done by the previous Government before announcing it would allow four-year-olds to start school.
"Without that evidence, I don't think that we can be confident... that is going to be good for every child."
NZEI president Lynda Stuart said kids are already starting school early enough.
Former Education Minister Nikki Kaye called the move "nanny state".