Logging out versus restarting

We as a company are running on a Novell Network, with workstations running NT. For the last year, we have been telling our end users to log off/and on as a different user at the end of the work day. There is a pocket of us that would rather see staff doing a restart and/or a power down. We believe some of our apps are causing us problems because of memory leaks. What I am looking for is any recommendation or confirmation that a restart is better than a logout that I can put in front of our executive staff that states that from whomever (Microsoft, Gartner, etc)this is the recommended procedure. Can you help?