store revenues are recorded at the time of sale and online store revenues are recorded upon delivery to the customer. 

In some instances, we ship product directly from our supplier to the customer and recognize revenue when the product is delivered to and accepted by the customer. Our revenues may fluctuate in cases when our customers delay accepting shipment of product for periods of up to several weeks. 

In certain countries outside of the United States, precise information regarding the date of receipt by the customer is not readily available. In these cases, we estimate the date of receipt by the customer based upon historical delivery times by geographic location. On the basis of our tests of actual transactions, we have no indication that these estimates have been materially inaccurate historically. 

As part of our revenue recognition policy, we record estimated sales returns, discounts and miscellaneous claims from customers as reductions to revenues at the time revenues are recorded. Our post invoice sales discounts consist of contractual programs with certain customers or discretionary discounts that are expected to be granted to certain customers at a later date. We base our estimates on historical rates of product returns, discounts and claims, specific identification of outstanding claims and outstanding returns not yet received from customers and estimated returns, discounts and claims expected but not yet finalized with our customers. Actual returns, discounts and claims in any future period are inherently uncertain and thus may differ from our estimates. If actual or expected future returns, discounts and claims were significantly greater or lower than the reserves we had established, we would record a reduction or increase to net revenues in the period in which we made such determination. 

Allowance for Uncollectible Accounts Receivable 

We make ongoing estimates relating to the ability to collect our accounts receivable and maintain an allowance for estimated losses resulting from the inability of our customers to make required payments. In determining the amount of the allowance, we consider our historical level of credit losses and make judgments about the creditworthiness of significant customers based on ongoing credit evaluations. Since we cannot predict future changes in the financial stability of our customers, actual future losses from uncollectible accounts may differ from our estimates. If the financial condition of our customers were to deteriorate, resulting in their inability to make payments, a larger allowance might be required. In the event we determine that a smaller or larger allowance is appropriate, we would record a credit or a charge to Operating overhead expense in the period in which such a determination is made. 

Inventory Reserves 

We also make ongoing estimates relating to the net realizable value of inventories based upon our assumptions about future demand and market conditions. If we estimate that the net realizable value of our inventory is less than the cost of the inventory recorded on our books, we record a reserve equal to the difference between the cost of the inventory and the