I'm a network/server admin and I would not recommend rebooting servers if there is no real reason...its just asking for trouble really. Servers are designed to run for months on end, we have several servers here that have not been rebooted for over 6 months. I've supported a lot of different networks at different companies and never seen anyone reboot servers on a schedule for no real reason. The way I see it, server reboots are a last resort to fix a problem or update something and should not be done for any other reason.