Margen
Every month, your paycheck faithfully pays the landlord, the supermarket, the power company and the streaming services. You get whatever's left, which many months is nothing. Paying yourself first means flipping that around: the day you get paid, an automatic transfer moves a portion —even just 50 €— to an account you don't see, before the spending begins.
The order matters more than the amount. If you save what's left over, spending expands until nothing is left; if you set money aside first, spending adapts to what remains. It's the same income behaving in two opposite ways.
And automation is the other half of the trick: a decision made just once saves you twelve willpower battles a year. No one forgets to pay you if the bank does it for you.