I rarely if ever carry cash. Nearly every transaction I make is via credit card. The only time I'll usually have cash is when traveling overseas (for emergencies, in the foreign currency, not USD). I find cash terribly inconvenient and annoying to use.

Meanwhile my wife loves using cash. I don't understand it. It's not for any privacy or idealogical reason - she says she just likes the old fashioned feel of handling physical money. She doesn't understand my dislike of using cash. As I said, we've agreed to disagree.

Every now and then when we're out together we'll encounter the rare merchant that doesn't accept credit card. Then she'll spot me with her cash. Otherwise we'll typically use our joint credit card. When she is out by herself she's much more likely to use the cash she always carries.