An image forming system having a preceding stage apparatus for forming a toner image on a paper sheet, and a subsequent stage apparatus, connected downstream of the preceding stage apparatus, for forming a toner image on the paper sheet ejected from the preceding stage apparatus, includes: a first maintenance counter correlating with a part, subject to maintenance, in the preceding stage apparatus; a second maintenance counter correlating with a part, subject to maintenance, in the subsequent stage apparatus, in response to the first maintenance counter; a counter control section for increasing a count value of the first and the second maintenance counters by a first and a second designated value, respectively, in response to formation of a toner image on the paper sheet; and a setting section for setting the first and second designated values individually based on an operation mode of the image forming system.