Every parent or older sibling knows the scene. Your teenager or twenty-something comes home radiating excitement over a pair of sneakers that cost as much as a used car. Or a limited-edition gaming controller. Or a mystery box from a YouTuber. The packaging is shiny, the dopamine is real, and the regret usually arrives about three weeks later when the credit card statement lands. If you’re trying to teach a young adult to control splurging, you already know that nagging doesn’t work. What does work is a concrete, almost boring system that lets them feel in control. The best one I’ve found is called the Two-Night Rule.

Here’s how it goes. Any time your young adult wants to buy something that isn’t a true necessity, they have to write the item down on a piece of paper or in a phone note, along with the price and the date. Then they wait. Two full nights must pass before they’re allowed to purchase it. That doesn’t mean they can’t think about it. They can think all they want. They can research, compare prices, read reviews. They just can’t click “buy” or hand over cash until two good nights of sleep have happened after their initial urge. If they still want it after that waiting period, they buy it without any guilt from you. No side-eyes, no “I told you so.“ The rule isn’t about preventing all spending. It’s about separating the urge from the action.

Why two nights and not one or seven? Because the most dangerous impulse purchases are driven by an emotional spike. Maybe they’re stressed about finals, bored on a Tuesday, or watching a friend unbox the same thing on Instagram. That spike rarely lasts beyond a few hours. But one night of sleep can still leave them half-convinced the purchase was a brilliant idea. Two nights gives the excitement time to cool down enough for their actual preferences to show up. By the second morning, many items start to look less like treasures and more like overpriced clutter. If it’s still genuinely valuable to them after that emotional reset, then it’s a legitimate splurge, not an impulse.

This works for a few psychological reasons. First, it converts an automatic reaction into a deliberate decision. When you force a pause, you force the brain to re-evaluate the trade-off between the money and the item. Second, it gives young adults a sense of ownership over their own spending. They’re not being forbidden anything. They’re being asked to demonstrate patience, which is a skill they’ll need for every major financial decision later in life. Third, the act of writing it down externalizes the desire, making it easier to examine. A vague “I want that” becomes a specific “I want this object, for this price, on this date.“ That’s much easier to argue with rationally.

You can adapt the rule for different ages and income levels. For a fourteen-year-old spending their allowance, the threshold might be twenty dollars. For a twenty-two-year-old with a part-time job, it might be seventy-five. The key is to set a number that feels meaningful but not impossible. And you should use the rule yourself, even on your own purchases. Nothing teaches better than example. When your teenager sees you writing down a potential new grill or a pair of designer boots and then actually walking away for two days, they understand this isn’t a punishment. It’s a habit.

Does the Two-Night Rule guarantee they’ll never splurge on junk again? No. They’ll still blow money on things you’d never buy, and that’s fine. The goal isn’t to turn them into miserly robots. It’s to teach them the difference between a decision made by a fleeting craving and a decision made by a stable preference. Buying a concert ticket they’ve been planning for three months is not an impulse. Buying a fifty-dollar app subscription at 2 a.m. because they couldn’t sleep is exactly the kind of thing the rule will stop.

One more benefit? The waiting period gives them time to actually compare prices and find a better deal. They might discover the same item is fifteen dollars cheaper on another site, or that a refurbished version works just as well. That’s where your bargain-hunting instincts finally rub off on them. But don’t lead with that point. Lead with the self-respect angle. Controlling splurges isn’t about deprivation. It’s about making sure your money buys things that matter to you, not just things that briefly looked exciting.

The next time your young adult is about to drop a paycheck on something they described as “amazing” but can’t explain why they need it, don’t fight them. Just pull out a notepad and say, “Nice. Write it down, and let’s see if it makes sense on Thursday.“ Then hand them the pen. The silence will do your arguing for you.