The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Because these estimates and assumptions require significant judgment, actual results could differ from those estimates and could have a significant impact on our results of operations, financial position and cash flows. We reevaluate our estimates and assumptions as needed, but at a minimum on a quarterly basis. The most significant estimates include, but are not limited to, inventory valuation, inventory reserves, warranty accrual, workers' compensation accrual, medical insurance accrual, income taxes, useful lives of property, plant, and equipment, estimated future use of leased property, share-based compensation, business combinations, revenue percentage of completion and estimated costs to complete. Actual results could differ materially from those estimates.

During the first quarter of 2022, a review of the Company’s useful lives for certain sheet metal manufacturing equipment at our Longview, Texas location resulted in a change in estimate that increased the useful lives from between ten and twelve years to fifteen years. This determination was based on recent and estimated future production levels as well as management’s knowledge of the equipment and historical and future use of the equipment. The change in estimate was made prospectively and resulted in a decrease to depreciation expense within cost of sales on our consolidated statements of income of $1.8 million during the nine months ended September 30, 2022.

A comprehensive discussion of our critical accounting policies and management estimates is included in Management’s Discussion and Analysis of Financial Condition and Results of Operations in our Annual Report on Form 10-K for the year ended December 31, 2021.

The carrying amounts of cash and cash equivalents, receivables, accounts payable, and accrued liabilities approximate fair value because of the short-term maturity of the items. The carrying amount of the Company’s revolving line of credit, and other payables, approximate their fair values either due to their short term nature, the variable rates associated with the debt or based on current rates offered to the Company for debt with similar characteristics.

Goodwill represents the excess of the consideration paid for the acquired businesses over the fair value of the individual assets acquired, net of liabilities assumed. At September 30, 2022 $50.3 million of goodwill is deductible for income tax purposes. Our indefinite-lived intangible assets consist of trademark and trade names. Goodwill and indefinite-lived intangible assets are not amortized, but instead are evaluated for impairment at least annually. We perform our annual assessment of impairment during the fourth quarter of our fiscal year, and more frequently if circumstances warrant.

Changes to U.S. GAAP are established by the Financial Accounting Standards Board ("FASB") in the form of Accounting Standards Updates ("ASUs") to the FASB's Accounting Standards Codification ("ASC"). We consider the applicability and impact of all ASUs. ASUs not listed or included within the Company's Annual Report on Form 10-K for the year ended December 31, 2021,2022, were assessed and determined to be either not applicable or are expected to have minimal impact on our consolidated financial statements and notes thereto.

We are responsible for billings and collections resulting from all sales transactions, including those initiated by our independent manufacturer representatives (“Representatives”). Representatives are national companies that are in the business of providing HVAC units and other related products and services to customers. The end user customer orders a bundled group of products and services from the Representative and expects the Representative to fulfill the order. These additional products and services may include controls purchased from another manufacturer to operate the unit, start-up services, and curbs for supporting the unit (“Third Party Products”). All are associated with the purchase of a HVAC unit but may be provided by the Representative or another third party. Only after the specifications are agreed to by the Representative and the customer, and the decision is made to use an AAON HVAC unit, will we receive notice of the order. We establish the amount we must receive for our HVAC unit (“minimum sales price”), but do not control the total order price that is negotiated by the Representative with the end user customer. The Representatives submit the total order price to us for invoicing and collection. The total order price includes our minimum sales price and an additional amount which may include both the Representatives’ fee and amounts due for additional products and services required by the customer. The Company is considered the principal for the equipment we design and manufacture and records that revenue. The Company has no control over the Third Party Products to the end customer and the Company is under no obligation related to the Third Party Products. Amounts related to Third Party Products are not recognized as revenue but are recorded as a liability and are included in accrued liabilities on the consolidated balance sheet.