What That Thing Actually Cost You

Say you bought an air fryer for $340. Seven months later it is in the donation pile.

The price tag says $340. The more useful number is $48.57, because that is what it cost you for every month it sat in your kitchen. One of those numbers tells you something about your next purchase. The other one does not.

Why the price tag is the wrong number

A price is a single fact about a single moment. It tells you what left your account. It says nothing about whether the thing earned its place.

A $900 washing machine you use for eleven years costs about $7 a month. A $60 gadget you use twice costs $30 a month. The expensive one is the cheap one, and you cannot see that from the price at all.

This is why cheap purchases quietly do more damage than expensive ones. Nobody agonises over $60. But $60 spent six times a year, on things that last five months, adds up faster than the one considered purchase you spent a fortnight thinking about.

How to work it out

The calculation is deliberately simple. Purchase price, divided by the number of months you owned it.

• A $340 air fryer kept seven months: about $49 a month.
• A $189 desk converter kept fourteen months: about $14 a month.
• A $45 yoga mat kept five months: about $9 a month.
• A $220 coffee grinder kept thirty-one months: about $7 a month.

You can do it on your phone in ten seconds. The maths is not the hard part.

The hard part is knowing when it ended

Here is why almost nobody has this number, despite the arithmetic being trivial. You need three pieces of information, and most people only ever record one.

• What it cost. Most people can find this if they look.
• When it arrived. Harder, but usually reconstructible.
• When it left. Almost nobody records this. It is the missing piece.

Buying is a documented event. There is a receipt, a bank line, an email. Getting rid of something is undocumented. It goes in a bag, the bag goes in the car, the car goes to the op shop, and nothing anywhere records that the item existed for eleven months and then stopped.

Without that third date you can never work out what anything actually cost. Which is why the moment something leaves is worth fifteen seconds of your attention.

What the number is good for

One number on its own is mildly interesting. A few dozen is something else.

Once you have thirty or forty, you stop looking at individual items and start seeing categories. Kitchen appliances might be the thing you release fastest. Tools might be the thing you never regret. Clothes might split cleanly into two groups with nothing in between.

That pattern is more useful than any budgeting rule, because it is about you specifically. General advice about spending applies to everyone and therefore to no one. Your own history applies precisely.

What it is not for

This number is not a score, and it is worth being clear about that.

Some things are meant to be short-lived. A cot lasts two years because a baby stops being a baby. A textbook lasts a semester. Camping gear you used hard for one summer and then sold did its job. A high cost per month is not automatically a mistake.

The point is not to feel bad about numbers. It is to notice which categories keep producing the same result, so the next time something similar catches your eye, you already know how the story tends to go.

Try it on one thing

Pick something you got rid of in the last year. Guess what it cost. Guess how long you had it. Divide.

Most people find the first number surprising. That surprise is the whole point, and it is available right now, with no app and no system, on the things you have already let go of.

Buoycott is being built to capture exactly this, in about fifteen seconds an item. It is an Australian decluttering tool for the home and for personal spending. Join the waitlist to hear when it launches. Join the waitlist →