Saving by decision is hard. Saving by default is easy. Round-ups turn paying off debt into something that happens on its own.
The problem with willpower
Most money advice asks you to make the right decision over and over: skip the coffee, move money to savings, pay extra this month. Every one of those is a chance to say "next time." Willpower runs out; defaults don't.
How a round-up works
Every purchase rounds up to the next dollar. A $3.80 coffee becomes $4.00, and the $0.20 is set aside. Across normal spending, the average round-up is about half a dollar.
Based on an average round-up of $0.50 per purchase.
Why it feels painless
Each round-up is too small to register as a sacrifice, and you decide only once, when you set it up. That's the same reason automatic retirement contributions work: when the good choice is the default, people stick with it.
Don't try to be disciplined every day. Make one good decision once and let it repeat.
This tip is general education, not financial advice. Examples are illustrative; your balances, rates and card terms will change the numbers.