While the Trace option can provide details on sessions and protocol issues, it can slow down a server with a lot of active sessions and chew-up a lot of disk space.
If you are having issues with user sessions seeming to end too quickly (timeout? web socket breaking? whatever?) -- you can turn-on this setting to activate session life-cycle tracing to unique log files, one per session ID (starting at 1 to maximum concurrent sessions).
Log files will be in the active Log Files Folder with a name "Sessions_n.log" where the (n) is the session ID 1..max.