A diagnostic system that effectively presents optimum products to the
users by effectively using information about the use history of an image
forming apparatus used by the users and other information specific to the
image forming apparatus that may be stored in advance. The diagnostic
system includes a management device that receives and manages management
information including at least information of print volume of an image
forming apparatus for a predetermined period, a determination device that
determines an optimum image forming apparatus based on the information of
print volume in the predetermined period managed by the management
device, and a notification device that notifies information indicative of
the optimum image forming apparatus determined by the determination
device to an information processing apparatus that is capable of
communication via a communication line.