i have to agree as well, that by not taking credit cards, you would be missing a lot of potential sales. another thing to consider is that many people use dbit cards, that are linked to their banking accounts, so that they can use it just like a credit card and also as to not to have to carry cash.
in the small town i live near, there is one radiator repair shop and he does mainly cash business and doesn't take credit cards. my brother subs his work through his shop because he does take credit cards and just tacks on a small fee to cover his expenses. if another radiator repair shop came into town that did take credit cards, it would probably cut heavily into his business. i now when i take work to him, i have to take cash or a check to pay for it.