Can I extend the session timeout?
The session timeout (the time of inactivity it takes before you're logged out) is a tradeoff between convenience, security and performance.
Longer sessions may be more convenient, but at the risk of reduced security (people often just walk away from their PCs), and reduced site performance, as the web server needs to keep track of more open sessions.
Presently, timeout occurs after about 20 minutes of inactivity. Sometimes this is less, because if the web server is under increased load it will reduce the timeout for a while to improve access speed.
The 20-minute inactivity limit is pretty much an industry-standard convention, chosen to balance these competing objectives. Long activities like creating an article or a mailing, where the server doesn't see any backwards and forwards activity, should always be recovered when the user logs back in.