Originally from the UK, Ms Smith said it was during a shopping trip in London along Oxford Street that made her realise she needed to make a change to her spending habits — but had no idea how much she'd actually save from culling shopping from her life.
"It was before Christmas, and people were shopping as if the world was ending," she said. "They were all trying to find the perfect gift for people who have everything. On New Year's Eve, I made the decision I wasn't going to buy anything new or second hand for 12 months and see how much I would save."
For Ms Smith, the promise proved hard to keep, and by April she'd "failed" when purchasing a pair of pants while on holiday in Noosa.
"I thought about it for the rest of 2013," she said. "It made me really angry."
When 2014 rolled around, she decided to give it another try. This time, she succeeded. Nothing new, or even second hand — Ms Smith limited herself to only buying household essentials for 12 months. The result? A cool $52,000 of savings in the bank.
"There were reasons for my impulse shopping," she explained. "I'd reward myself for working long hours. I was earning more than ever, but also working longer hours. So I would treat myself to new clothes or simply go for a shop.
"The other reason was boredom. It's easy to go to the shops if there is nothing else to do during your lunch break. Before you know it you've got heaps of stuff you don't need … especially if you're shopping with peers because it's really easy to be influenced in to buying."
Ms Smith, since doing the spending experiment four years ago, said she now implements a "three month waitlist" when it comes to buying clothing, household or items for leisure.
"Before 2014, I didn't have a record of what I was buying," she said. "It's so easy to do … and most of us have no idea how much we spend on a daily, weekly or monthly basis. Eighty per cent of us don't keep a record. It's just part of the daily habit.
"Now, if I want to buy something new, I will write it down and have a waiting list which shows the item, price and the date which I can buy it. I quite often find myself not wanting it by the time the date rolls around."
Ms Smith, who now teaches others how to break the habit of impulse buying, says she would swap clothes, books, magazines and movies with friends as a way of beating the urge to buy something new, as well as focusing on experiences.
"I'd go for walks or go kayaking, horse riding or stand-up paddle boarding. I'd find out about free workshops or movies and festivals in my local area."
Ms Smith said her top tips for people wanting to cut down their spend include:
1. Have a waiting list on items you'd like to buy. Even if it's just a week. If you're still keen on the purchase one week or one month down the track, then consider buying. But avoid impulse shopping.
2. Sort out all the things you have — soaps, shampoo, shoes and clothes. Even going through your pantry, people often have so much stored away and waiting to be used. Most people could live out of their pantry for weeks.
3. Finally, make an emergency savings account. Even if you're only putting away a small portion of your income, it means if something does go wrong — a large expense or you lose your job — there is money to fall back on.
"After that first year, I had saved over NZ$56,000 and not long after, I was made redundant," Ms Smith added.
"So I thought this is a great time to write a book, Underspent, and share my story, because after that redundancy, a lot of my colleagues were highly stressed because they had zero savings."
