While developing Burning MUD, we encountered a rather interesting phenomenon: our mud was up for so long, that players were literally begging us to reboot it every few days. This "problem" was corrected in several ways: First, almost all reboot-only equipment (equipment that only loads in the game after a reboot) was removed. Second, we implemented automatic reboot system. This system reboots the mud every 31 hours.
However it does more that just that. To eliminate the problem with lost gold, experience, or equipment as a result of reboots, BurningMUD now automatically retrieves corpses and saves all players in the game before a reboot. The gods can also change the time until the next reboot, if they have reason to reboot at a different time, and as the reboot draws near you are regularly notified of how long until the next reboot.