This article is from the eBay FAQ, by William B. Shaw email@example.com with numerous contributions by others.
They are available on eBay's site for a minimum of 90 days. This is the same
as the length of time guaranteed for leaving feedback on an auction.
Completed items are only available through My EBay for 30 days and via
search for 10 days (subject to change without notice). After 30 days, you
need to know the auction number to view the listing.