Server Reset/Update Times?

Just out of curiosity,

does anyone know what the server reset or update times are for WOTLK realms and how often? (i.e. daily, weekly etc.)

Asking particularly for Lordaeron. I don't know if all wrath realms are updated together or if each realm is seperate.

usually there is a realm restart for updates on monday morning (lordaeron/icecrown/outland)

So once per week basically ( I am not sure if it is the same for MoP realm)