Good Morning Everyone!
We currently have the time out setting in Vista set for 60 minutes. That is a very long time in terms of lab security. Consider the student working in a common lab setting -- s/he logs into his account, spends 5 or 10 minutes on classwork, then leaves without logging out. The next student sits down at the computer and discovers he can access the previous student's class. I'd like to believe there is no potential for trouble in that scenario, but have become more cynical than that.
On the other hand, we have you the instructor writing a discussion post. You get half-way finished, then are distracted by other urgent student emails. When you return you have been timed-out and your half-finished post is lost. If you haven't clicked you are timed-out, so spending a lot of time writing a post or setting up groups can cause lost work.
Given those two scenarios, what is the most appropriate amount of time before the system logs you out? I tend to think 60 minutes is too long and 15 minutes (recommended) is too short. Folks with strong opinions should comment on this blog post (so everyone else can read your opinions, as opposed to just me).