Service Center Manuals contain a plethora of information, including topics on policies, procedures, diagramed schematics, hardware specifications, software updates, new product announcements, service bulletins, advertisement ideas and much more! Though Service Centers were required to have a copy of the Guidelines Manual, the other manuals seem to have been optional for purchase. Also, not many Service Centers needed any of the other manuals since they were not contracted to complete any serious repairs on Nintendo products. Most manual pages have revision dates listed on the top right corner of the page, and as such were updated when new products became available, when new repair techniques were introduced, when certain policies changed or when inaccuracies or misinformation were found.