It also depends on your volume of client purchases on credit cards. I am a niche photo studio and I don't have a huge number of transactions every month, but each one is larger than an average photography invoice. When it is time to pay the invoice, I urge my clients to use checks to pay me as it saves me on credit card fees. Most of my clients are sympathetic to a small business person and they are also sensitive to the degree in which credit card clearing houses disproportionately penalize small business (ESPECIALLY American Express).
In Fiscal Year 2015, I paid just short of $2,000.00 in credit card fees to card clearing companies for the "convenience" of having my clients use credit cards. This $2,000.00 number is smaller than it WOULD have been due to the fact that I am able to convince roughly half of my clients who initially pull out a credit card to put the card back up and to write me a check.
I have several invoices a month that are between $1,000.00 and $2,000.00. When someone asks if they can pay with a credit card, I cringe. When you see the line item credit card fees for each $1,000.00+ transaction on your monthly statement, it puts the impact of credit card fees to your bottom line into perspective quickly.
Summarily, my prices are set to factor in all fixed and variable costs, including my annual credit card fees. These fees are ultimately an ugly CODB that we all must bear, so price accordingly.