I am looking for any information on preventative maintenance on an 8" bench grinder that is used in a Machine Shop. I have the daily check information, but need to know if there is any particular monthly, yearly checks that have to be done.

Hi,
Most high quality bench grinders require no maintenance. They are brushless and sealed.
Just clean the area around it. Replace stones as needed.
Peace,
Clarke

The grinding wheel should be checked for tightness. The grinding wheel should be dressed with a dressing tool if the wheel is not flat on the face. Ensure that the tool rest are properly adjusted and tight. Not much else to do.