The inability of most companies to double-check every bill that comes through their accounting departments has spawned an industry of specialized auditors. These businesses comb through bills -- telephone, utilities, medical, an travel and entertainment -- with an eye toward catching incorrect charges, overcharges, and a variety of other costly errors. Assuming that you don't have the staff to examine every payment your company makes, here are three areas that may be ripe for an audit.

* Worker's compensation claims: Because doctors generally bill a business's insurance company directly for medical services, the concern doesn't get an itemized account of what it has actually paid for. An Inglewood, Calif., company will look at every claim for the most recent three years, including disability, attorneys' fees, hospital costs, and other medical payments, and balance those amounts against a company's insurance coverage. The business insurance administration service, ISCS Ltd., can figure out whether its client is entitled to receive money back from the insurance company, whether it is properly insured, or if any of its policies overlap. It will also audit current claims, and counsel injured employees on their rights and options.

* Freight changes: Nolan & Cunnings Inc., of Warren, Mich., determines whether a company is paying the correct rates for freight, both shipped and received. It also suggests which carriers should be used, and provides distribution reports on every item transported. New Century Freight Traffic Association Inc., in Chicago, examines air cargo, railroad, and truckline bills for the past three years, and files overcharge claims on its clients' behalf with the carriers.

* Legal fees: Risk Analysis & Management Corp., of St. Louis, reviews legal bills, including depositions, interrogatories, and travel expenses. Risk Analysis determines whether each charge is fully documented, necessary, and in accordance with American Bar Association guidelines. For example, a $1-million automobile dealership had a liability case that went to court. The company won, but it was saddled with a legal fee of about $62,750. An audit determined that the services performed were worth only $44,000. The law firm knocked $10,000 off the dealership's bill.