"They are boys and they are sporty. They need something to do during the day.
"It's still at the affordable stage for us. We are expecting that with cricket, you'll get to that point where you have to sit down and say 'what are we doing here - are you going to become Black Caps or what'?"
It's not all about sport for the O'Sullivan boys, who also take piano lessons, adding another $1,960 to their personal development bill.
It's similar for the Lewis family. Six-year-old Brocky studies a martial art ($340 a term) and plays soccer ($200 a season for fees and gear). Mum Michelle would like 3-year-old Trinity to have dancing and swimming lessons but Brocky's expenses mean something has to give.
"We're in that position where we are on one income so I can be with the kids. So I am available to take them to activities but it is being able to afford the activities," Ms Lewis says. "Then it's finding the balance between what is too much and what is too little."
New Zealand's biggest sporting code goes out of its way to be accessible to all, New Zealand Rugby Union community rugby manager Brent Anderson says.
Fees can be as low as $5. Unlike soccer and netball, the national body doesn't charge an affiliation levy.
"It's the opposite," says Mr Anderson. "We provide $18 million to the provincial unions, based on registered player numbers, to keep costs as low as possible and help run the game. We think the kids and the parents and families are getting a great deal from rugby."
Most sports don't enjoy rugby's financial resources. After six years of not charging a levy, Netball New Zealand has reintroduced charges of $2.50 a season for junior players and $4.50 for seniors.
Even so, netball is one of the more affordable sporting codes, with junior fees in Auckland around the $80 mark.
"We think it is good value," said Netball NZ's operations director, Kate Agnew. "The objective is to remain affordable and accessible."
Decreased access to Community Trust funding was a factor in the reintroduction of the levy.
Rugby league maintains it is the most affordable game to play. At the Mangere East Hawks, junior fees are $20 and capped at $40 per family, so a family with five kids would pay only $8 a child for the season.
That sort of pricing is an issue for a sport not flush with cash, says Counties Manukau zone general manager Kasey King.
"It is affordable. You can pay $1 a week and still have your kid playing rugby league. We are encouraging the clubs to take a look at that because it is so cheap. The same families will play another code and pay up to $100 registration."
Registration fees are a vexed issue at the Howick-Pakuranga Cricket Club.
Fees that start at $125 for midgets and climb to $340 as players age are too high say the members, but they don't cover costs that include an administration staff and a coaching director, former Black Cap Dipak Patel.
Members are not prepared to fundraise, says administration officer Pam Phillips. They fundraise all winter for the rugby "and they are tired of it by the time summer comes".
