They run monthly Credit Checks and if they do not like your credit score, they will close your account. The 1 time credit check to open the credit card is not a one time thing. I paid on time and paid off my balances every single time. I lost my job and couldn't afford to pay my credit card off for 1 month.
A similar survey by the American Medical Group Association rated orthopedic spinal surgeons as the highest-paid of all physicians at a median income of $688,503 per year. Orthopedic joint replacement surgeons were second at $605,953 per year, ahead of neurosurgeons at $592,811.
The type of Dr who makes the most money directly from medicine (discounting those who earn most from their hospital or health companies) in my area is well-respected (so can set his or her own fees high), does procedures (for which you can charge a great deal - they do not necessarily have to be surgery - psychiatrists who do lots of ECT and dermatologists who do lots of procedures can also earn a great deal) and works long hours.