Maintenance is a fact of life. If you own a PC with Virus protection Software, you’ll receive maintenance updates for the virus detection files. If you PC is Windows based, there are periodic Operating System updates to ensure that the bad guys don’t get in there and reek havoc with your system. eBay is subject to similar maintenance, on a much larger scale. While they get the virus updates and operating system updates, they also have server specific software that requires updates. They also have mirrored systems placed around the country (and world), synchronized to provide you with timely access. Each system requires maintenance. During the maintenance periods, response time is not as good, and if you are the buyer, you can really jump in and get some great deals. As a seller, you want to make sure that none of your auctions end during the maintenance period as you want as many people as possible to have access to your auction.
EBay publishes their planned maintenance schedule regularly. Be sure to visit their System Announcement page to plan your auction timing accordingly.