Maintenance Windows for Networks Spanning Multiple Time Zones

[tex () delamancha org]

Folks,

  I am looking for input from other providers as to how they handle
maintenance windows when their networks span multiple time zones.

  I would imagine that common windows are not expected to span more than
3 or 4 timezones due to the difficulty of finding a large enough block
of time that works for all of the time zones in that window.

  So, what do you folks do?

-tex