Getting married will change your cash-carrying habits!!! I used to keep about a hundred dollars on me. Never spent it, was just able to carry it in case I saw something I HAD to have, or needed cab fare or a tow.
With the wife and kids always "I need a twenty, you got one or two?" With no cash in my pocket, I no longer have any cash available for them. Works well.
I use the debit card for EVERYTHING. Even fast food these days. Of course, the only problem is being tracked by THE MAN, with every transaction recorded.