https://www.youtube.com/watch?v=np5i5oWfqAo
12-18% additional spending from using credit card vs cash.
The part about bartering was very interesting. When you hand cash over, you get your goods. It was a transaction. Your brain registers this. When you use a credit card, you still get the credit card back along with the items you purchased. Your brain does not register this the same way.
In other words, he's saying cash makes you a thrifty consumer.
Well, I don't know that I'll be switching but that's interesting.