SERVER APPARATUS THAT CALCULATES RESIDUAL SERVICE LIFE OF REPLACEABLE UNIT ON BASIS OF OBSERVATION DATA ACQUIRED FROM IMAGE FORMING APPARATUS, RESIDUAL SERVICE LIFE PREDICTION SYSTEM, AND IMAGE FORMING APPARATUS

A server apparatus including a first communication device and a first computing device. The first communication device communicates with an image forming apparatus via a network. The first computing device includes a processor, and acts as a data acquirer, a dimension reduction processor, and a residual service life calculator, when the processor executes a first control program. The data acquirer acquires observation data of a first number of dimensions from the image forming apparatus, via the first communication device. The dimension reduction processor converts the observation data of the first number of dimensions into characteristic data of a second number of dimensions fewer than the first number of dimensions. The residual service life calculator calculates a residual service life of a replaceable unit in the image forming apparatus, on a basis of the characteristic data.