Revenues Revenue for periods through December 30, 2017 was reported under Accounting Standards Codification (ASC) 605, Revenue Recognition (Topic 605) , as described in our accounting policies in our 2017 Form 10-K. Effective December 31, 2017, we adopted ASC 606, Revenue From Contracts With Customers (Topic 606) (ASC 606). The results of applying Topic 606 using the modified retrospective approach were insignificant and did not have a material impact on our consolidated financial condition, results of operations, cash flows, business process, controls or systems. ASC 606 defines a performance obligation as a promise in a contract to transfer a distinct good or service to the customer and is considered the unit of account. The majority of our contracts have one single performance obligation as the promise to transfer the individual goods is not separately identifiable from other promises in the contracts and is, therefore, not distinct. Discounts and incentives are treated as separate performance obligations. We allocate the contracts transaction price to each of these performance obligations separately using explicitly stated amounts or our best estimate using historical data. Additionally, we estimate and record gift card breakage as redemptions occur. In accordance with ASC 606 revenue is recognized at the time the sale is made, at which time our walk-in customers take immediate possession of the merchandise or same-day delivery is made to our Professional delivery customers, which include certain independently-owned store locations. Payment terms are established for our Professional delivery customers based on pre-established credit requirements. Payment terms vary depending on the customer and generally range from 1 to 30 days. Based on the nature of receivables, no significant financing components exist. For e-commerce sales, revenue is recognized either at the time of pick-up at one of our store locations or at the time of shipment depending on the customer's order designation. Sales are recorded net of discounts, sales incentives and rebates, sales taxes and estimated returns and allowances. We estimate the reduction to Net sales and Cost of sales for returns based on current sales levels and our historical return experience. We provide assurance type warranty coverage primarily on batteries, brakes and struts whereby we are required to provide replacement product at no cost or a reduced cost for a set period of time. We had no material contract assets, contract liabilities or costs to obtain and fulfill contracts recorded on the Condensed Consolidated Balance Sheet as of October 6, 2018 . For the twelve and forty weeks ended October 6, 2018 , revenue recognized from performance obligations related to prior periods (for example, due to changes in transaction price) was insignificant. Revenue expected to be recognized in future periods related to remaining performance obligations is insignificant.