That means setting up a floating portion of your mortgage and have all your income going into that account during the month. You'll pay all your bills on your credit card, so more money sits in the account and you accrue less interest. At the end of the month, you clear your credit cards. This can substantially reduce your overall interest bill but be careful not to get carried away on the plastic.
Check your bills
It's worth regularly checking that you're getting the best deal on household expenses such as power and phone. Websites such as powerswitch.co.nz will tell you whether you could cut your energy bill - and even the way you use your power can save money.
Wellington mum Catherine Wieblitz is saving by running everything at night when the power cost is lower. She's using a Genesis smart meter and app to monitor her usage. "Our night-store heaters turn on after 11pm, if I need to use the dryer I'll put it on after 1pm and we're currently trialling having our hot water cylinder heat up overnight instead of during the day."
Discounts are often available for phone and internet services if you're willing to bundle your accounts. Te Atatu woman Jaynie Ball gets $30 a month off her broadband from Vodafone because her partner's mobile is with them. Vodafone also offers Sky discounts to broadband customers.
Telecom will give $10 "Bundle Up Bonus" to customers who have an Ultra Mobile plan and an eligible home broadband plan with Telecom.
Consumer's TelMe site allows you to compare options for mobile, landline, internet and TV.
Most phone and broadband providers will help you get on to the right plan but you'll have to ring and ask.
Review your insurance
If you have a house, contents or car insurance policy coming up for renewal, shop around.
Terry Jordan, of the Insurance Council, says it's worth getting two or three quotes.
If you're worried about your premiums, opt for a higher excess. Jordan says his house insurance policy offers a $400 excess for $1958 a year, or a $5000 excess for $1626. He said this was a good option for people who viewed insurance as a backstop for cases of total disaster.
Bank fees
Get a breakdown of the fees you pay and compare them to what's available elsewhere. Accounts vary a lot - even something like an eftpos transaction can be free with one account but cost 30c with another. What suits will depend on how you use your account, but don't make the expensive mistake of using a savings account for day-to-day banking.
Fees for dishonoured transactions are pricey. BNZ does not charge dishonour fees for cheques and electronic payments. All the other banks do, up to about $20 a time.
If you need an overdraft, arrange one. You will have to pay to set it up but it is cheaper over the long term as most banks charge about $10 when you stray into the red.
Also, check your credit card balance. If you're not paying it off each month, you could save by taking advantage of a balance transfer rate. as low as 1 per cent at present.
The waste of money adds up
Hannah McQueen, of financial advice firm EnableMe, says people fritter away up to 20 per cent of their income without realising it.
Her team first helped Jessica Brandford-Borgfeldt and her husband, Sam Borgfeldt, four years ago. The pair had to account for all their spending, which made them more aware of the way little things would add up.
"You need to know where your money is going. They got us to keep our receipts and put them into a spreadsheet. It was onerous but you don't realise how much you throw away," Borgfeldt said.
Brandford-Borgfeldt said: "You might buy a coffee a day, if you think about how much that is over the year you start thinking about it differently."
It wasn't until she kept records that she found she was spending as much as $65 a week on lunches.
