Here's a tip - WAIT to pay your provider bills until you've received confirmation from your insurance.
Since every claim must be submitted to your insurance first, you'll receive a statement from your carrier for everything. The statement is called an EOB (Explanation of Benefits).
One big problem is that some providers (not all) like to get paid right away, and don't bother to wait for the insurance company. So, they send the bill to you, the same time they send it to your insurance. Since the billed amount is usually higher than the insurance company's "allowed amount", if you pay the bill, you will more than likely pay too much.
What's worse, the provider may not refund you the overage, they may just give you a "credit" towards you next visit.
So, the solution? Make a file that you drop every doctor invoice into. As soon as your insurance company sends you an EOB, pull out the file and match the doctor's invoice with the EOB. If it matches, pay the doctor. If it doesn't, call the doctor's office and request a corrected invoice.
This way, you can be sure to never over-pay for your patient responsibility costs.
Note - be sure you don't wait longer than 30 days to call your provider's billing department, as some providers are quick to send you to collections.