I am not yet in operation, but I can say this….
In the DC metro area, people use their credit cards for meals, even cheap ones. I worked in corporate America for 15 years or so. Over the past several years in particular, I’ve noticed that just about every person I went to lunch with used one. We’re talking sandwiches, pizza, big lunches, etc. I preferred cash myself, but that’s beside the point. I think people find it lighter in the pocket and just plain easier to deal with the card. In the old days, transactions weren’t as seamless, but it’s quick now.
If you can afford to take cards, I’d do it. I plan to do so, as I honestly believe I could lose business by not accepting them.