Sally James does her grocery shopping every Thursday and for 17 years she has meticulously recorded everything she buys.
From groceries, petrol and homewares, James tracks all her spending habits and cashes that information in for rewards.
"I've mainly cashed my points in for gift cards so that means I can use them at whatever shops I want and buy whatever I want," she told 9News.
She's one of more than 13,000 Aussies whose spending habits are closely tracked by the IRI shopper panel.
The panel monitors spending habits across retailers from a major grocery chain, to a department store and even outdoor goods sellers.
"So there are two main groups of people who are interested in the data. That is the retailers who are trying to figure out what to put on the shelves and sell, and the manufacturers- the farmers the growers," Alistair Leathwood, from Circana the company responsible for IRI shopper panel, said.
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For the major grocery players information is key as each vie for greater profits and market share.
"Data is the number one priority for retailers - it is king for them to understand how customers are behaving and why they shop with them," The Retail Doctor Anastasia Lloyd-Wallis said.
