High net worth customers like to use Amex, though, so refusing to take it is not a good option.
Our business did NOT accept Amex.
For one, it was too easy for the customer to dispute the charges (which some do to try and scam you) and it was hell trying to get paid after a claim like that.
Plus the fees. We gave it up a dozen years ago. Visa, MC, and Paypal, check, money order, or cash (which we offered a 10% discount for) were our offerings. Take it or leave it, or find another contractor. We also did our financing through our own credit union / bank for big jobs. Too much risk for us to do the financing.