You made a budget in January. It was sensible, you both agreed to it, and by the second week of February you had stopped looking at it.

Most advice about budgeting as a couple is about setting one up. Setting one up was never the hard part. You did that in an evening.

The interesting question is why it died, because household budgets die of the same three things almost every time, and only one of them is about money.

Cause of death one: you wrote it from memory

Sit two people down and ask what they spend on groceries. They will confer, settle on a number that feels right, and write it in.

That number is almost always low, and predictably so. People recall fixed bills perfectly, because those are single memorable amounts that never change. Variable spending is forty small transactions a month, and nobody holds forty transactions in their head.

You will guess the rent to the dollar and the groceries by half.

So the budget is wrong on the day it is written, and wrong in a specific direction. Week three arrives, groceries are already over, and the obvious conclusion is that the budget does not work. The budget was fine. The inputs were fiction.

Do this instead

Open the last three months of statements. Total each category, divide by three, and use that as your opening number. It will be higher than you want it to be. That is the point of doing it.

Cause of death two: arguing about categories

Is a haircut a need? Is the coffee on the way to work groceries, or eating out, or personal spending?

These questions have no correct answers, they come up constantly, and every one is an opportunity for a small disagreement about somebody else’s habits. Enough of them and the budget stops being a plan and starts being a place where you get told off.

The fix is boring and it works: fewer categories. Six or seven, not twenty. If you cannot decide which of two categories something belongs to, that is a sign they should be one category.

The line that saves the whole thing

Each person gets an amount every month that they do not have to justify, account for, or discuss. It goes in the budget as a number and never as an itemised list.

This is not a treat. It is what stops the budget becoming a mechanism for supervising an adult, and that is the failure mode that ends marriages rather than budgets. Any purchase inside that number is simply not a household matter.

It works at any size. Sixty dollars each is enough if sixty is what there is. The amount matters far less than the fact that nobody has to ask.

Cause of death three: only one of you can see it

In most households one person builds the budget, one person maintains it, and one person knows what the position is. The other person finds out when they are told they have overspent.

That is not a shared budget. It is one person keeping accounts and another person being audited, and the audited party will disengage, because nobody volunteers for that.

Both people need to be able to look, without asking and without it being a conversation. The mechanics are the same problem shared calendars have, and the family calendar nobody uses goes through why an entry only ever reaches the person who opens the app.

The load underneath it is a bigger question again. Splitting the mental load is about the knowing rather than the doing, and a budget held in one head is a textbook case.

Deciding who puts in what

A household budget says what the house spends. It does not say who funds it, and those are separate arguments that get tangled together constantly.

Settle the total first, then the contributions. If your incomes are some distance apart, that second question has real subtleties, and splitting bills on unequal incomes covers what each method actually leaves each of you with.

One line in that total is almost always set too low, and it is the house itself. How much does it cost to run a house has the published figures and the method for turning the annual bills and the wearing-out into one monthly number.

The fifteen-minute review

1. Totals only. Six numbers against six budgets. Do not open the transactions.
2. Fix the budget, not the person. If food has been over three months running, food was set too low. That is data, not a failing.
3. One decision, then stop. Change one number a month. Changing five means you learn nothing from any of them.

Put it in the shared calendar. Fifteen minutes on the first Sunday is the difference between a budget that describes your life and one that describes January.

Common questions