Each session for items and checkout data have a specific timeout of 31 days. After a period of inactivity of 31 days passes, the items are deleted, and a new session is created the next time the code needs to reference items for that user.
- Items and checkout data are independent of each other and can have timeouts set individually.
- Items and checkout data timeouts can be changed independently for replicated sites and Back-office.
Also, is the shopping cart content specific to the computer upon which the user is initially signed on?
The items are saved on a session by session basis, this means that they are device specific in most cases since the session key is stored in a cookie on the user's machine. (in some cases like google chrome where session data and cookies are shared across multiple devices that the user is logged in to with a Google account, all devices shared in this manner would share items)