How long before system timeout should a warning appear?

1. How long should session timeout be?
2. How does session timeout work?

How long should session timeout be?

Typical session timeouts are 15- to 45-minute durations depending on the sensitivity of the data that may be exposed. As the session timeout is approaching, offer users a warning and give them an opportunity to stay logged in.

How does session timeout work?

Session timeout represents the event occuring when a user does not perform any action on a web site during an interval (defined by a web server). The event, on the server side, changes the status of the user session to 'invalid' (ie.