For a nonessential purchase, wait at least a day. For anything large, wait a week. Leave the item in the cart or on a list. If you still want it when the wait ends, and it fits the month’s plan, buy it. Many wants cool off. The ones that remain are easier to enjoy because you chose them twice.
You can also price the item in hours of work. Divide the price by your take-home hourly pay. The result is not a rule. It is a translation that makes an abstract price concrete.
Start this week
Start a note called “Later.” Add every nonessential you almost buy. At the end of the month, add up the ones you no longer want.