Credit Card Rewards Math

A typical "generous" cash-back card returns 2%. Spend $30,000 a year and you earn $600. Sounds great — until you learn that paying with a card quietly pushes that spending up.

The effect isn't about discipline — it's neurological. Swiping a card doesn't trigger the same pain as handing over cash. In one classic experiment, people were willing to pay up to twice as much for the same item when told they'd pay by card instead of cash. Rewards add a dopamine hit of "earning" on top of that painless payment — so the few hundred dollars you collect can be dwarfed by what the card nudged you to spend.