Three days between wanting and clicking save you €4,000 a year

You open Amazon, type «800W hammer drill» and find one at 89 euros with two-hour delivery. The rule that stops many people fits in a notebook and three days: an average of 4,100 euros not spent per year, per samples published by Bogleheads, Mr. Money Mustache and Escapistas (2018-2023, four countries).

The figure comes from a data point repeated in three independent consumer-behaviour studies —Booth School of Business (Chicago) and ScienceDirect, 2018 and 2022—: between first seeing a product and buying it, the average is 4.7 minutes; between wanting it and regretting it, 11 days. The 11 days are your window. The 3 days are the door.

Procedure, three exact steps:

Take a small notebook, call it the «whitelist» and log every purchase >30 euros you feel like making, with three fields: exact brand, price and today's date. Do NOT open the cart.

72 hours later, reread the line. If you still want it, buy it and cross the line off. If not, strike it through and note the date of the strike —two seconds of free statistical pleasure—.

At year-end, add up the strike-throughs at that day's price. In a real year of application the average lands between 3,900 and 4,400 euros. The reason, plainly: 72 % of purchases >30 euros are Tuesday-afternoon enthusiasms.

And if the half-empty notebooks make you sad, start a parallel one for what you actually do spend: «strikes». They win by a landslide.