An image forming apparatus of which maintenance work can always be conducted appropriately independent of time-degradation of the apparatus is provided. In the image forming apparatus of which maintenance work is done in accordance with either a user mode or a service engineer mode, an image forming unit including an image forming station prints an image in accordance with image data, and a main CPU calculates duration of use of the apparatus as an index indicating time-degradation, and determines whether or not the calculated duration of use of the apparatus has reached one year as a predetermined threshold value. Based on the result of determination, a user mode or a service engineer mode is set as a maintenance method for conducting maintenance work.