"Official" status of servers prior to reboot

Often, updates applied to servers require a reboot and the reboot nag
prompt understandably pops up at regular intervals. Of course, it makes
sense to reboot as soon as possible, but sometimes I come across 24x7
operations that leave servers in the nag screen state for days on end -
which I personally thing is not good. Is there an "official" MS
statement / guideline / best practice (something that I can print off
from MS's web site and show IT management to back my case) regarding
this as it makes me nervous leaving servers in this state?

Cheers