The order matters because each step removes a decision you would otherwise be making in a shop, under pressure. Rules first, then a place for wants to die, then the sourcing, then the repair, and only at the end the review, by which point the evidence has accumulated on its own.
Step 1: Define what counts as new
Ambiguity is what kills these months, so the definitions come first, before any temptation arrives. Write the yes and no columns on the strip itself: new means no; secondhand, borrowed, swapped, gifted, repaired and homemade all mean yes. Food and health are excluded outright - groceries, prescriptions, dentist, toothpaste, contact lenses. Anything else gets decided in advance, not in the aisle. A concrete test: a new bike inner tube is a repair, a new bike is not. Run three or four edge cases through the rule now - socks, phone case, birthday gift - and write the answers down. People usually announce the challenge publicly and leave the rules loose, which means every purchase turns into a private negotiation you can talk yourself out of by week two.
Step 2: Park every want on paper
Desire needs somewhere to go that is not a checkout page, and after step one the rules are set, so the only thing left to manage is the urge itself. Keep the list somewhere you will actually reopen it - the back of the strip, a notebook on the kitchen table. One line per item, with the date and the price you saw: "12 Sept - linen trousers, £40, charity shop on Mill Road." No justification, no ranking, no judgement. The point is delay, not denial. Most entries die on their own, which is exactly what should happen; a want that still looks reasonable three weeks later is a real signal, while one you have to reread to remember was a mood. Where this goes wrong is keeping the list in your head, where a passing urge feels identical to a genuine need by the time you are standing in the shop.
Step 3: Source three real needs secondhand
By now the list from step two has done its sorting, so you can see which entries are genuine needs rather than passing wants. Pick three of the needs - a winter coat, a kitchen chair, school shoes - and give yourself a hard two-week deadline on each, because a need without a deadline quietly becomes a new purchase in week four. Work four channels in this order: ask in a local swap group, check two charity shops within walking distance, search one online marketplace with saved alerts, then ask a neighbour or colleague. Be specific in your search terms: "size 10 waterproof walking boot", not "boots". Inspect before paying - check zips, soles, and whether the previous owner's smell is removable. The usual error is buying something secondhand purely to hit the number, which is still consumption: a £6 jacket you will never wear costs more than the £0 you did not spend.
Step 4: Repair instead of replacing
Repair comes after sourcing secondhand because it is the last cheap option before buying, and it applies to the item you have already mentally written off. Choose something specific: the lamp with the loose switch, the boots with worn soles, the chair with the wobbly leg, the coat with the broken zip. Search the exact model plus the word "repair", then look for a local repair cafe, a cobbler, or a YouTube teardown. Compare part cost to replacement cost out loud - an £8 cable against a £60 lamp is an easy call, a £90 repair on a £70 printer is not. Many people pick something that needs a specialist skill or an obsolete part, it sits broken on the floor for three weeks, and they buy the new one anyway, which makes the whole exercise feel pointless rather than instructive. Choose the repair you can finish.
Step 5: Write down what actually shifted
Only now does the evidence exist to write anything honest: the want list from step two, the three secondhand finds from step three, the one repair from step four. Reread the list and mark every line as bought, still wanted, or forgotten. Then write three short observations with numbers in them, because vague resolutions do not survive contact with a shop window. For example: "Everything under £15 was forgotten within a week. Nothing over £50 disappeared." or "I wanted three things; I needed one." Keep it to a single page and put a date on it. The frequent failure here is skipping the review altogether and starting next month with a good feeling and no record, or writing an aspiration like "be more mindful" that gives you nothing to check against. Numbers and dates are what make the lesson reusable.
A reminder on a phone disappears the moment you dismiss it and leaves nothing behind; a paper strip taped to a kitchen cupboard stays visible until the month ends, and it physically gets shorter as you cut steps off. The want list sits on the same strip, dated, which is harder to argue with in week three than a notification you already swiped away. Keep it where you make the decision, not where you feel good about it.