Let’s say that you run a bank. You decide to give more credit to your good customers. Should you give it those who increase their account balance by any amount (even as small as 1 euro) per year? Or to those who just maintain their account? Which offer would they find more appealing?

Now imagine that you are running a charity and you want to increase repeated donations. Should you ask your contributors to pre-commit to making the same donation again and again? Or should you ask them to pre-commit to increasing their donation every time they donate, even if the increase is just only 1 cent? Which setup would they find more motivating?

Can such small differences (1 euro, 1 cent, etc.) have an impact on consumer behavior, consumer welfare, and business outcomes? And what impact, exactly?