The paper investigates the degree to which buyers choose to diversify their use of payment methods for in-person purchases. Some buyers use only one payment instrument. Others combine the use of mostly cash, credit, debit cards, and a few paper checks and prepaid cards. To each survey respondent, I apply three concentration measures over the use of payment instruments. Results show that the degree of consumers' payment concentration exhibits almost no correlation with consumer demographics, payment volume, or aggregate value.