What is in this guide
Cost per use divides the price of something by how many times you realistically expect to use it, so a dearer item that gets used often can work out cheaper than a bargain that sits in a cupboard. It is one factor in a buying decision, not the only one, and it only helps once the number of uses is honest.
1. Work out the number first
Cost per use = purchase price divided by the realistic number of uses.
Take the full price, including anything added at checkout such as delivery, and divide it by how many times you expect the item to earn its keep before it wears out, breaks, is outgrown or is replaced for any other reason. The result is a dollar figure for a single use, and that figure is what is worth comparing between two options, not the sticker price alone.
This works for anything used repeatedly over time: a school backpack, a pram, a stand mixer, a dog bed, a pair of work boots. It is the wrong tool for something used once, such as a costume for a single event, and for consumables bought and used up on a normal shopping cycle. Comparing unit prices for household basics covers that second kind of purchase, where the comparison is price per litre or per hundred sheets rather than price per occasion.
2. Estimate uses honestly, not optimistically
The number of uses is the part most likely to go wrong, because it is tempting to assume frequent use for years when the real pattern is more irregular.
Base the estimate on how the item will actually be used in your household, not on how a similar item tends to be used generally. A slow cooker bought around firm weekly meal plans is a different sum to one bought on a whim with no particular meal in mind. A school bag used most of the year for several years is a different calculation again to a bag a child outgrows or wears out within one.
Build in a shorter life than you hope for, particularly for anything a child uses, anything exposed to weather, or anything with moving parts. A cautious estimate that still favours the dearer option is a stronger reason to buy it than an optimistic one that barely does.
3. Add what you can recover
Cost per use improves once you subtract what an item is worth at the end of its life, not just what it cost to buy.
Effective cost per use = (purchase price minus resale or trade-in value) divided by the realistic number of uses.
Items in a well-known brand, a common size, or a style that is not overly specific to one season tend to hold value better in genuine secondhand markets. Buying kids gear at the right time of year covers timing a purchase around the Australian retail calendar, which affects both the price paid up front and what the item might fetch later.
4. Check the price is real before you calculate anything
A cost-per-use sum is only as useful as the price that goes into it. Spotting false discounts and sale tactics is worth checking before relying on a was-now price, since an inflated “was” price makes the cheaper-looking option appear better value than it actually is.
5. Weigh it against the consumer guarantee, not instead of it
Price is not the only thing that should set your expectation of how long something will last. Under Australian Consumer Law, the acceptable-quality guarantee requires goods to be safe, durable and free from defects, among other things, and what counts as a reasonable length of time weighs the price paid against the nature of the goods, the ACCC explains. A cost-per-use calculation does not replace that guarantee. If an item fails well short of a reasonable time for its type and price, you may have a right to a remedy regardless of how the sum worked out beforehand.
Keeping receipts and warranty details for household purchases makes that guarantee easier to use when something does fail early, and it also makes a genuine resale value easier to establish later, since a receipt and any warranty paperwork answer the first question a secondhand buyer usually asks.
6. Make care part of the sum
How something is used and maintained changes the number of uses it survives, which changes the calculation without changing the price paid. Looking after non-stick pans so they last longer is one example: the same pan can last a noticeably different number of meals depending on how it is cleaned and stored, and the same logic applies to plenty of other household items.
One sum before your next purchase
Before buying a dearer option because it should “last”, write down the price, a realistic number of uses, and any amount you could recover later. Divide. Then compare that figure with the cheaper option’s own honest sum, not with its sticker price. The lower cost-per-use figure is the better buy only once both estimates are realistic, and only once the item still needs to do the job in the first place.
How we checked this: Checked against ACCC guidance on consumer rights and guarantees on 2 October 2026. The cost-per-use and effective-cost-per-use formulas are editorial arithmetic; no product lifespan, saving or test result is claimed.
The one-page family week
One printable page that holds the whole week: meals, school, activities and who is doing the pickup. Free, and we send one useful email a week.
One email a week. No spam, unsubscribe in a click.
